diff --git a/packages/react-devtools-extensions/package.json b/packages/react-devtools-extensions/package.json
index 40954c4425155..da473f7613a68 100644
--- a/packages/react-devtools-extensions/package.json
+++ b/packages/react-devtools-extensions/package.json
@@ -50,6 +50,7 @@
     "rollup-plugin-commonjs": "^9.3.4",
     "rollup-plugin-node-resolve": "^2.1.1",
     "source-map": "^0.8.0-beta.0",
+    "sourcemap-codec": "^1.4.8",
     "style-loader": "^0.23.1",
     "web-ext": "^3.0.0",
     "webpack": "^4.43.0",
diff --git a/packages/react-devtools-extensions/src/__tests__/__source__/__compiled__/no-columns/ComponentWithCustomHook.js b/packages/react-devtools-extensions/src/__tests__/__source__/__compiled__/no-columns/ComponentWithCustomHook.js
new file mode 100644
index 0000000000000..07c3317e87d32
--- /dev/null
+++ b/packages/react-devtools-extensions/src/__tests__/__source__/__compiled__/no-columns/ComponentWithCustomHook.js
@@ -0,0 +1,41 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.Component = Component;
+
+var _react = _interopRequireWildcard(require("react"));
+
+function _getRequireWildcardCache() { if (typeof WeakMap !== "function") return null; var cache = new WeakMap(); _getRequireWildcardCache = function () { return cache; }; return cache; }
+
+function _interopRequireWildcard(obj) { if (obj && obj.__esModule) { return obj; } if (obj === null || typeof obj !== "object" && typeof obj !== "function") { return { default: obj }; } var cache = _getRequireWildcardCache(); if (cache && cache.has(obj)) { return cache.get(obj); } var newObj = {}; var hasPropertyDescriptor = Object.defineProperty && Object.getOwnPropertyDescriptor; for (var key in obj) { if (Object.prototype.hasOwnProperty.call(obj, key)) { var desc = hasPropertyDescriptor ? Object.getOwnPropertyDescriptor(obj, key) : null; if (desc && (desc.get || desc.set)) { Object.defineProperty(newObj, key, desc); } else { newObj[key] = obj[key]; } } } newObj.default = obj; if (cache) { cache.set(obj, newObj); } return newObj; }
+
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+function Component() {
+  const [count, setCount] = (0, _react.useState)(0);
+  const isDarkMode = useIsDarkMode();
+  (0, _react.useEffect)(() => {// ...
+  }, []);
+
+  const handleClick = () => setCount(count + 1);
+
+  return /*#__PURE__*/_react.default.createElement(_react.default.Fragment, null, /*#__PURE__*/_react.default.createElement("div", null, "Dark mode? ", isDarkMode), /*#__PURE__*/_react.default.createElement("div", null, "Count: ", count), /*#__PURE__*/_react.default.createElement("button", {
+    onClick: handleClick
+  }, "Update count"));
+}
+
+function useIsDarkMode() {
+  const [isDarkMode] = (0, _react.useState)(false);
+  (0, _react.useEffect)(function useEffectCreate() {// Here is where we may listen to a "theme" event...
+  }, []);
+  return isDarkMode;
+}
+//# sourceMappingURL=data:application/json;charset=utf-8;base64,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
\ No newline at end of file
diff --git a/packages/react-devtools-extensions/src/__tests__/__source__/__compiled__/no-columns/ComponentWithExternalCustomHooks.js b/packages/react-devtools-extensions/src/__tests__/__source__/__compiled__/no-columns/ComponentWithExternalCustomHooks.js
new file mode 100644
index 0000000000000..63c7ec8d8ef9e
--- /dev/null
+++ b/packages/react-devtools-extensions/src/__tests__/__source__/__compiled__/no-columns/ComponentWithExternalCustomHooks.js
@@ -0,0 +1,26 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.Component = Component;
+
+var _react = _interopRequireDefault(require("react"));
+
+var _useTheme = _interopRequireDefault(require("./useTheme"));
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
+
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+function Component() {
+  const theme = (0, _useTheme.default)();
+  return /*#__PURE__*/_react.default.createElement("div", null, "theme: ", theme);
+}
+//# sourceMappingURL=data:application/json;charset=utf-8;base64,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
\ No newline at end of file
diff --git a/packages/react-devtools-extensions/src/__tests__/__source__/__compiled__/no-columns/ComponentWithMultipleHooksPerLine.js b/packages/react-devtools-extensions/src/__tests__/__source__/__compiled__/no-columns/ComponentWithMultipleHooksPerLine.js
new file mode 100644
index 0000000000000..b05cd188f4686
--- /dev/null
+++ b/packages/react-devtools-extensions/src/__tests__/__source__/__compiled__/no-columns/ComponentWithMultipleHooksPerLine.js
@@ -0,0 +1,30 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.Component = Component;
+
+var _react = require("react");
+
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+const A = /*#__PURE__*/(0, _react.createContext)(1);
+const B = /*#__PURE__*/(0, _react.createContext)(2);
+
+function Component() {
+  const a = (0, _react.useContext)(A);
+  const b = (0, _react.useContext)(B); // prettier-ignore
+
+  const c = (0, _react.useContext)(A),
+        d = (0, _react.useContext)(B); // eslint-disable-line one-var
+
+  return a + b + c + d;
+}
+//# sourceMappingURL=data:application/json;charset=utf-8;base64,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
\ No newline at end of file
diff --git a/packages/react-devtools-extensions/src/__tests__/__source__/__compiled__/no-columns/ContainingStringSourceMappingURL.js b/packages/react-devtools-extensions/src/__tests__/__source__/__compiled__/no-columns/ContainingStringSourceMappingURL.js
new file mode 100644
index 0000000000000..a05ba5ba69824
--- /dev/null
+++ b/packages/react-devtools-extensions/src/__tests__/__source__/__compiled__/no-columns/ContainingStringSourceMappingURL.js
@@ -0,0 +1,29 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.Component = Component;
+
+var _react = _interopRequireWildcard(require("react"));
+
+function _getRequireWildcardCache() { if (typeof WeakMap !== "function") return null; var cache = new WeakMap(); _getRequireWildcardCache = function () { return cache; }; return cache; }
+
+function _interopRequireWildcard(obj) { if (obj && obj.__esModule) { return obj; } if (obj === null || typeof obj !== "object" && typeof obj !== "function") { return { default: obj }; } var cache = _getRequireWildcardCache(); if (cache && cache.has(obj)) { return cache.get(obj); } var newObj = {}; var hasPropertyDescriptor = Object.defineProperty && Object.getOwnPropertyDescriptor; for (var key in obj) { if (Object.prototype.hasOwnProperty.call(obj, key)) { var desc = hasPropertyDescriptor ? Object.getOwnPropertyDescriptor(obj, key) : null; if (desc && (desc.get || desc.set)) { Object.defineProperty(newObj, key, desc); } else { newObj[key] = obj[key]; } } } newObj.default = obj; if (cache) { cache.set(obj, newObj); } return newObj; }
+
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+// ?sourceMappingURL=([^\s'"]+)/gm
+function Component() {
+  const [count, setCount] = (0, _react.useState)(0);
+  return /*#__PURE__*/_react.default.createElement("div", null, /*#__PURE__*/_react.default.createElement("p", null, "You clicked ", count, " times"), /*#__PURE__*/_react.default.createElement("button", {
+    onClick: () => setCount(count + 1)
+  }, "Click me"));
+}
+//# sourceMappingURL=data:application/json;charset=utf-8;base64,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
\ No newline at end of file
diff --git a/packages/react-devtools-extensions/src/__tests__/__source__/__compiled__/no-columns/Example.js b/packages/react-devtools-extensions/src/__tests__/__source__/__compiled__/no-columns/Example.js
new file mode 100644
index 0000000000000..6d668eaac8a14
--- /dev/null
+++ b/packages/react-devtools-extensions/src/__tests__/__source__/__compiled__/no-columns/Example.js
@@ -0,0 +1,28 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.Component = Component;
+
+var _react = _interopRequireWildcard(require("react"));
+
+function _getRequireWildcardCache() { if (typeof WeakMap !== "function") return null; var cache = new WeakMap(); _getRequireWildcardCache = function () { return cache; }; return cache; }
+
+function _interopRequireWildcard(obj) { if (obj && obj.__esModule) { return obj; } if (obj === null || typeof obj !== "object" && typeof obj !== "function") { return { default: obj }; } var cache = _getRequireWildcardCache(); if (cache && cache.has(obj)) { return cache.get(obj); } var newObj = {}; var hasPropertyDescriptor = Object.defineProperty && Object.getOwnPropertyDescriptor; for (var key in obj) { if (Object.prototype.hasOwnProperty.call(obj, key)) { var desc = hasPropertyDescriptor ? Object.getOwnPropertyDescriptor(obj, key) : null; if (desc && (desc.get || desc.set)) { Object.defineProperty(newObj, key, desc); } else { newObj[key] = obj[key]; } } } newObj.default = obj; if (cache) { cache.set(obj, newObj); } return newObj; }
+
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+function Component() {
+  const [count, setCount] = (0, _react.useState)(0);
+  return /*#__PURE__*/_react.default.createElement("div", null, /*#__PURE__*/_react.default.createElement("p", null, "You clicked ", count, " times"), /*#__PURE__*/_react.default.createElement("button", {
+    onClick: () => setCount(count + 1)
+  }, "Click me"));
+}
+//# sourceMappingURL=data:application/json;charset=utf-8;base64,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
\ No newline at end of file
diff --git a/packages/react-devtools-extensions/src/__tests__/__source__/__compiled__/no-columns/InlineRequire.js b/packages/react-devtools-extensions/src/__tests__/__source__/__compiled__/no-columns/InlineRequire.js
new file mode 100644
index 0000000000000..45f22810dfbe1
--- /dev/null
+++ b/packages/react-devtools-extensions/src/__tests__/__source__/__compiled__/no-columns/InlineRequire.js
@@ -0,0 +1,21 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.Component = Component;
+
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+function Component() {
+  const [count] = require('react').useState(0);
+
+  return count;
+}
+//# sourceMappingURL=data:application/json;charset=utf-8;base64,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
\ No newline at end of file
diff --git a/packages/react-devtools-extensions/src/__tests__/__source__/__compiled__/no-columns/ToDoList.js b/packages/react-devtools-extensions/src/__tests__/__source__/__compiled__/no-columns/ToDoList.js
new file mode 100644
index 0000000000000..3693681e10871
--- /dev/null
+++ b/packages/react-devtools-extensions/src/__tests__/__source__/__compiled__/no-columns/ToDoList.js
@@ -0,0 +1,106 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.ListItem = ListItem;
+exports.List = List;
+
+var React = _interopRequireWildcard(require("react"));
+
+function _getRequireWildcardCache() { if (typeof WeakMap !== "function") return null; var cache = new WeakMap(); _getRequireWildcardCache = function () { return cache; }; return cache; }
+
+function _interopRequireWildcard(obj) { if (obj && obj.__esModule) { return obj; } if (obj === null || typeof obj !== "object" && typeof obj !== "function") { return { default: obj }; } var cache = _getRequireWildcardCache(); if (cache && cache.has(obj)) { return cache.get(obj); } var newObj = {}; var hasPropertyDescriptor = Object.defineProperty && Object.getOwnPropertyDescriptor; for (var key in obj) { if (Object.prototype.hasOwnProperty.call(obj, key)) { var desc = hasPropertyDescriptor ? Object.getOwnPropertyDescriptor(obj, key) : null; if (desc && (desc.get || desc.set)) { Object.defineProperty(newObj, key, desc); } else { newObj[key] = obj[key]; } } } newObj.default = obj; if (cache) { cache.set(obj, newObj); } return newObj; }
+
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+function ListItem({
+  item,
+  removeItem,
+  toggleItem
+}) {
+  const handleDelete = (0, React.useCallback)(() => {
+    removeItem(item);
+  }, [item, removeItem]);
+  const handleToggle = (0, React.useCallback)(() => {
+    toggleItem(item);
+  }, [item, toggleItem]);
+  return /*#__PURE__*/React.createElement("li", null, /*#__PURE__*/React.createElement("button", {
+    onClick: handleDelete
+  }, "Delete"), /*#__PURE__*/React.createElement("label", null, /*#__PURE__*/React.createElement("input", {
+    checked: item.isComplete,
+    onChange: handleToggle,
+    type: "checkbox"
+  }), ' ', item.text));
+}
+
+function List(props) {
+  const [newItemText, setNewItemText] = (0, React.useState)('');
+  const [items, setItems] = (0, React.useState)([{
+    id: 1,
+    isComplete: true,
+    text: 'First'
+  }, {
+    id: 2,
+    isComplete: true,
+    text: 'Second'
+  }, {
+    id: 3,
+    isComplete: false,
+    text: 'Third'
+  }]);
+  const [uid, setUID] = (0, React.useState)(4);
+  const handleClick = (0, React.useCallback)(() => {
+    if (newItemText !== '') {
+      setItems([...items, {
+        id: uid,
+        isComplete: false,
+        text: newItemText
+      }]);
+      setUID(uid + 1);
+      setNewItemText('');
+    }
+  }, [newItemText, items, uid]);
+  const handleKeyPress = (0, React.useCallback)(event => {
+    if (event.key === 'Enter') {
+      handleClick();
+    }
+  }, [handleClick]);
+  const handleChange = (0, React.useCallback)(event => {
+    setNewItemText(event.currentTarget.value);
+  }, [setNewItemText]);
+  const removeItem = (0, React.useCallback)(itemToRemove => setItems(items.filter(item => item !== itemToRemove)), [items]);
+  const toggleItem = (0, React.useCallback)(itemToToggle => {
+    // Dont use indexOf()
+    // because editing props in DevTools creates a new Object.
+    const index = items.findIndex(item => item.id === itemToToggle.id);
+    setItems(items.slice(0, index).concat({ ...itemToToggle,
+      isComplete: !itemToToggle.isComplete
+    }).concat(items.slice(index + 1)));
+  }, [items]);
+  return /*#__PURE__*/React.createElement(React.Fragment, null, /*#__PURE__*/React.createElement("h1", null, "List"), /*#__PURE__*/React.createElement("input", {
+    type: "text",
+    placeholder: "New list item...",
+    value: newItemText,
+    onChange: handleChange,
+    onKeyPress: handleKeyPress
+  }), /*#__PURE__*/React.createElement("button", {
+    disabled: newItemText === '',
+    onClick: handleClick
+  }, /*#__PURE__*/React.createElement("span", {
+    role: "img",
+    "aria-label": "Add item"
+  }, "Add")), /*#__PURE__*/React.createElement("ul", null, items.map(item => /*#__PURE__*/React.createElement(ListItem, {
+    key: item.id,
+    item: item,
+    removeItem: removeItem,
+    toggleItem: toggleItem
+  }))));
+}
+//# sourceMappingURL=data:application/json;charset=utf-8;base64,{"version":3,"sources":["ToDoList.js"],"names":["ListItem","item","removeItem","toggleItem","handleDelete","handleToggle","isComplete","text","List","props","newItemText","setNewItemText","items","setItems","id","uid","setUID","handleClick","handleKeyPress","event","key","handleChange","currentTarget","value","itemToRemove","filter","itemToToggle","index","findIndex","slice","concat","map"],"mappings":";;;;;;;;AASA;;;;;;AATA;;;;;;;;AAYA,SAAAA,QAAA,CAAA;AAAAC,EAAAA,IAAA;AAAAC,EAAAA,UAAA;AAAAC,EAAAA;AAAA,CAAA,EAAA;AACA,QAAAC,YAAA,GAAA,uBAAA,MAAA;AACAF,IAAAA,UAAA,CAAAD,IAAA,CAAA;AACA,GAFA,EAEA,CAAAA,IAAA,EAAAC,UAAA,CAFA,CAAA;AAIA,QAAAG,YAAA,GAAA,uBAAA,MAAA;AACAF,IAAAA,UAAA,CAAAF,IAAA,CAAA;AACA,GAFA,EAEA,CAAAA,IAAA,EAAAE,UAAA,CAFA,CAAA;AAIA,sBACA,6CACA;AAAA,IAAA,OAAA,EAAAC;AAAA,cADA,eAEA,gDACA;AACA,IAAA,OAAA,EAAAH,IAAA,CAAAK,UADA;AAEA,IAAA,QAAA,EAAAD,YAFA;AAGA,IAAA,IAAA,EAAA;AAHA,IADA,EAKA,GALA,EAMAJ,IAAA,CAAAM,IANA,CAFA,CADA;AAaA;;AAEA,SAAAC,IAAA,CAAAC,KAAA,EAAA;AACA,QAAA,CAAAC,WAAA,EAAAC,cAAA,IAAA,oBAAA,EAAA,CAAA;AACA,QAAA,CAAAC,KAAA,EAAAC,QAAA,IAAA,oBAAA,CACA;AAAAC,IAAAA,EAAA,EAAA,CAAA;AAAAR,IAAAA,UAAA,EAAA,IAAA;AAAAC,IAAAA,IAAA,EAAA;AAAA,GADA,EAEA;AAAAO,IAAAA,EAAA,EAAA,CAAA;AAAAR,IAAAA,UAAA,EAAA,IAAA;AAAAC,IAAAA,IAAA,EAAA;AAAA,GAFA,EAGA;AAAAO,IAAAA,EAAA,EAAA,CAAA;AAAAR,IAAAA,UAAA,EAAA,KAAA;AAAAC,IAAAA,IAAA,EAAA;AAAA,GAHA,CAAA,CAAA;AAKA,QAAA,CAAAQ,GAAA,EAAAC,MAAA,IAAA,oBAAA,CAAA,CAAA;AAEA,QAAAC,WAAA,GAAA,uBAAA,MAAA;AACA,QAAAP,WAAA,KAAA,EAAA,EAAA;AACAG,MAAAA,QAAA,CAAA,CACA,GAAAD,KADA,EAEA;AACAE,QAAAA,EAAA,EAAAC,GADA;AAEAT,QAAAA,UAAA,EAAA,KAFA;AAGAC,QAAAA,IAAA,EAAAG;AAHA,OAFA,CAAA,CAAA;AAQAM,MAAAA,MAAA,CAAAD,GAAA,GAAA,CAAA,CAAA;AACAJ,MAAAA,cAAA,CAAA,EAAA,CAAA;AACA;AACA,GAbA,EAaA,CAAAD,WAAA,EAAAE,KAAA,EAAAG,GAAA,CAbA,CAAA;AAeA,QAAAG,cAAA,GAAA,uBACAC,KAAA,IAAA;AACA,QAAAA,KAAA,CAAAC,GAAA,KAAA,OAAA,EAAA;AACAH,MAAAA,WAAA;AACA;AACA,GALA,EAMA,CAAAA,WAAA,CANA,CAAA;AASA,QAAAI,YAAA,GAAA,uBACAF,KAAA,IAAA;AACAR,IAAAA,cAAA,CAAAQ,KAAA,CAAAG,aAAA,CAAAC,KAAA,CAAA;AACA,GAHA,EAIA,CAAAZ,cAAA,CAJA,CAAA;AAOA,QAAAT,UAAA,GAAA,uBACAsB,YAAA,IAAAX,QAAA,CAAAD,KAAA,CAAAa,MAAA,CAAAxB,IAAA,IAAAA,IAAA,KAAAuB,YAAA,CAAA,CADA,EAEA,CAAAZ,KAAA,CAFA,CAAA;AAKA,QAAAT,UAAA,GAAA,uBACAuB,YAAA,IAAA;AACA;AACA;AACA,UAAAC,KAAA,GAAAf,KAAA,CAAAgB,SAAA,CAAA3B,IAAA,IAAAA,IAAA,CAAAa,EAAA,KAAAY,YAAA,CAAAZ,EAAA,CAAA;AAEAD,IAAAA,QAAA,CACAD,KAAA,CACAiB,KADA,CACA,CADA,EACAF,KADA,EAEAG,MAFA,CAEA,EACA,GAAAJ,YADA;AAEApB,MAAAA,UAAA,EAAA,CAAAoB,YAAA,CAAApB;AAFA,KAFA,EAMAwB,MANA,CAMAlB,KAAA,CAAAiB,KAAA,CAAAF,KAAA,GAAA,CAAA,CANA,CADA,CAAA;AASA,GAfA,EAgBA,CAAAf,KAAA,CAhBA,CAAA;AAmBA,sBACA,oBAAA,cAAA,qBACA,uCADA,eAEA;AACA,IAAA,IAAA,EAAA,MADA;AAEA,IAAA,WAAA,EAAA,kBAFA;AAGA,IAAA,KAAA,EAAAF,WAHA;AAIA,IAAA,QAAA,EAAAW,YAJA;AAKA,IAAA,UAAA,EAAAH;AALA,IAFA,eASA;AAAA,IAAA,QAAA,EAAAR,WAAA,KAAA,EAAA;AAAA,IAAA,OAAA,EAAAO;AAAA,kBACA;AAAA,IAAA,IAAA,EAAA,KAAA;AAAA,kBAAA;AAAA,WADA,CATA,eAcA,gCACAL,KAAA,CAAAmB,GAAA,CAAA9B,IAAA,iBACA,oBAAA,QAAA;AACA,IAAA,GAAA,EAAAA,IAAA,CAAAa,EADA;AAEA,IAAA,IAAA,EAAAb,IAFA;AAGA,IAAA,UAAA,EAAAC,UAHA;AAIA,IAAA,UAAA,EAAAC;AAJA,IADA,CADA,CAdA,CADA;AA2BA","sourcesContent":["/**\n * Copyright (c) Facebook, Inc. and its affiliates.\n *\n * This source code is licensed under the MIT license found in the\n * LICENSE file in the root directory of this source tree.\n *\n * @flow\n */\n\nimport * as React from 'react';\nimport {Fragment, useCallback, useState} from 'react';\n\nexport function ListItem({item, removeItem, toggleItem}) {\n  const handleDelete = useCallback(() => {\n    removeItem(item);\n  }, [item, removeItem]);\n\n  const handleToggle = useCallback(() => {\n    toggleItem(item);\n  }, [item, toggleItem]);\n\n  return (\n    <li>\n      <button onClick={handleDelete}>Delete</button>\n      <label>\n        <input\n          checked={item.isComplete}\n          onChange={handleToggle}\n          type=\"checkbox\"\n        />{' '}\n        {item.text}\n      </label>\n    </li>\n  );\n}\n\nexport function List(props) {\n  const [newItemText, setNewItemText] = useState('');\n  const [items, setItems] = useState([\n    {id: 1, isComplete: true, text: 'First'},\n    {id: 2, isComplete: true, text: 'Second'},\n    {id: 3, isComplete: false, text: 'Third'},\n  ]);\n  const [uid, setUID] = useState(4);\n\n  const handleClick = useCallback(() => {\n    if (newItemText !== '') {\n      setItems([\n        ...items,\n        {\n          id: uid,\n          isComplete: false,\n          text: newItemText,\n        },\n      ]);\n      setUID(uid + 1);\n      setNewItemText('');\n    }\n  }, [newItemText, items, uid]);\n\n  const handleKeyPress = useCallback(\n    event => {\n      if (event.key === 'Enter') {\n        handleClick();\n      }\n    },\n    [handleClick],\n  );\n\n  const handleChange = useCallback(\n    event => {\n      setNewItemText(event.currentTarget.value);\n    },\n    [setNewItemText],\n  );\n\n  const removeItem = useCallback(\n    itemToRemove => setItems(items.filter(item => item !== itemToRemove)),\n    [items],\n  );\n\n  const toggleItem = useCallback(\n    itemToToggle => {\n      // Dont use indexOf()\n      // because editing props in DevTools creates a new Object.\n      const index = items.findIndex(item => item.id === itemToToggle.id);\n\n      setItems(\n        items\n          .slice(0, index)\n          .concat({\n            ...itemToToggle,\n            isComplete: !itemToToggle.isComplete,\n          })\n          .concat(items.slice(index + 1)),\n      );\n    },\n    [items],\n  );\n\n  return (\n    <Fragment>\n      <h1>List</h1>\n      <input\n        type=\"text\"\n        placeholder=\"New list item...\"\n        value={newItemText}\n        onChange={handleChange}\n        onKeyPress={handleKeyPress}\n      />\n      <button disabled={newItemText === ''} onClick={handleClick}>\n        <span role=\"img\" aria-label=\"Add item\">\n          Add\n        </span>\n      </button>\n      <ul>\n        {items.map(item => (\n          <ListItem\n            key={item.id}\n            item={item}\n            removeItem={removeItem}\n            toggleItem={toggleItem}\n          />\n        ))}\n      </ul>\n    </Fragment>\n  );\n}\n"]}
\ No newline at end of file
diff --git a/packages/react-devtools-extensions/src/__tests__/__source__/__compiled__/no-columns/index.js b/packages/react-devtools-extensions/src/__tests__/__source__/__compiled__/no-columns/index.js
new file mode 100644
index 0000000000000..186ab68d95aab
--- /dev/null
+++ b/packages/react-devtools-extensions/src/__tests__/__source__/__compiled__/no-columns/index.js
@@ -0,0 +1,73 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+Object.defineProperty(exports, "ComponentWithCustomHook", {
+  enumerable: true,
+  get: function () {
+    return _ComponentWithCustomHook.Component;
+  }
+});
+Object.defineProperty(exports, "ComponentWithExternalCustomHooks", {
+  enumerable: true,
+  get: function () {
+    return _ComponentWithExternalCustomHooks.Component;
+  }
+});
+Object.defineProperty(exports, "ComponentWithMultipleHooksPerLine", {
+  enumerable: true,
+  get: function () {
+    return _ComponentWithMultipleHooksPerLine.Component;
+  }
+});
+Object.defineProperty(exports, "ContainingStringSourceMappingURL", {
+  enumerable: true,
+  get: function () {
+    return _ContainingStringSourceMappingURL.Component;
+  }
+});
+Object.defineProperty(exports, "Example", {
+  enumerable: true,
+  get: function () {
+    return _Example.Component;
+  }
+});
+Object.defineProperty(exports, "InlineRequire", {
+  enumerable: true,
+  get: function () {
+    return _InlineRequire.Component;
+  }
+});
+Object.defineProperty(exports, "useTheme", {
+  enumerable: true,
+  get: function () {
+    return _useTheme.default;
+  }
+});
+exports.ToDoList = void 0;
+
+var _ComponentWithCustomHook = require("./ComponentWithCustomHook");
+
+var _ComponentWithExternalCustomHooks = require("./ComponentWithExternalCustomHooks");
+
+var _ComponentWithMultipleHooksPerLine = require("./ComponentWithMultipleHooksPerLine");
+
+var _ContainingStringSourceMappingURL = require("./ContainingStringSourceMappingURL");
+
+var _Example = require("./Example");
+
+var _InlineRequire = require("./InlineRequire");
+
+var ToDoList = _interopRequireWildcard(require("./ToDoList"));
+
+exports.ToDoList = ToDoList;
+
+var _useTheme = _interopRequireDefault(require("./useTheme"));
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
+
+function _getRequireWildcardCache() { if (typeof WeakMap !== "function") return null; var cache = new WeakMap(); _getRequireWildcardCache = function () { return cache; }; return cache; }
+
+function _interopRequireWildcard(obj) { if (obj && obj.__esModule) { return obj; } if (obj === null || typeof obj !== "object" && typeof obj !== "function") { return { default: obj }; } var cache = _getRequireWildcardCache(); if (cache && cache.has(obj)) { return cache.get(obj); } var newObj = {}; var hasPropertyDescriptor = Object.defineProperty && Object.getOwnPropertyDescriptor; for (var key in obj) { if (Object.prototype.hasOwnProperty.call(obj, key)) { var desc = hasPropertyDescriptor ? Object.getOwnPropertyDescriptor(obj, key) : null; if (desc && (desc.get || desc.set)) { Object.defineProperty(newObj, key, desc); } else { newObj[key] = obj[key]; } } } newObj.default = obj; if (cache) { cache.set(obj, newObj); } return newObj; }
+//# sourceMappingURL=data:application/json;charset=utf-8;base64,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
\ No newline at end of file
diff --git a/packages/react-devtools-extensions/src/__tests__/__source__/__compiled__/no-columns/useTheme.js b/packages/react-devtools-extensions/src/__tests__/__source__/__compiled__/no-columns/useTheme.js
new file mode 100644
index 0000000000000..7a1b76c59c002
--- /dev/null
+++ b/packages/react-devtools-extensions/src/__tests__/__source__/__compiled__/no-columns/useTheme.js
@@ -0,0 +1,27 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.default = useTheme;
+exports.ThemeContext = void 0;
+
+var _react = require("react");
+
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+const ThemeContext = /*#__PURE__*/(0, _react.createContext)('bright');
+exports.ThemeContext = ThemeContext;
+
+function useTheme() {
+  const theme = (0, _react.useContext)(ThemeContext);
+  (0, _react.useDebugValue)(theme);
+  return theme;
+}
+//# sourceMappingURL=data:application/json;charset=utf-8;base64,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
\ No newline at end of file
diff --git a/packages/react-devtools-extensions/src/__tests__/parseHookNames-test.js b/packages/react-devtools-extensions/src/__tests__/parseHookNames-test.js
index a1429ec7587d0..2599ce95c4cd3 100644
--- a/packages/react-devtools-extensions/src/__tests__/parseHookNames-test.js
+++ b/packages/react-devtools-extensions/src/__tests__/parseHookNames-test.js
@@ -172,6 +172,7 @@ describe('parseHookNames', () => {
       await test('./__source__/__compiled__/inline/Example'); // inline source map
       await test('./__source__/__compiled__/external/Example'); // external source map
       await test('./__source__/__compiled__/bundle/index', 'Example'); // bundle source map
+      await test('./__source__/__compiled__/no-columns/Example'); // simulated Webpack 'cheap-module-source-map'
     });
 
     it('should work with more complex files and components', async () => {
@@ -203,6 +204,7 @@ describe('parseHookNames', () => {
       await test('./__source__/__compiled__/inline/ToDoList'); // inline source map
       await test('./__source__/__compiled__/external/ToDoList'); // external source map
       await test('./__source__/__compiled__/bundle', 'ToDoList'); // bundle source map
+      await test('./__source__/__compiled__/no-columns/ToDoList'); // simulated Webpack 'cheap-module-source-map'
     });
 
     it('should work for custom hook', async () => {
@@ -220,6 +222,9 @@ describe('parseHookNames', () => {
       await test('./__source__/__compiled__/inline/ComponentWithCustomHook'); // inline source map
       await test('./__source__/__compiled__/external/ComponentWithCustomHook'); // external source map
       await test('./__source__/__compiled__/bundle', 'ComponentWithCustomHook'); // bundle source map
+      await test(
+        './__source__/__compiled__/no-columns/ComponentWithCustomHook',
+      ); // simulated Webpack 'cheap-module-source-map'
     });
 
     it('should work for external hooks', async () => {
@@ -245,6 +250,9 @@ describe('parseHookNames', () => {
         './__source__/__compiled__/bundle',
         'ComponentWithExternalCustomHooks',
       ); // bundle source map
+      await test(
+        './__source__/__compiled__/no-columns/ComponentWithExternalCustomHooks',
+      ); // simulated Webpack 'cheap-module-source-map'
     });
 
     it('should work when multiple hooks are on a line', async () => {
@@ -269,6 +277,24 @@ describe('parseHookNames', () => {
         './__source__/__compiled__/bundle',
         'ComponentWithMultipleHooksPerLine',
       ); // bundle source map
+
+      async function noColumnTest(path, name = 'Component') {
+        const Component = require(path)[name];
+        const hookNames = await getHookNamesForComponent(Component);
+        expectHookNamesToEqual(hookNames, [
+          'a', // useContext()
+          'b', // useContext()
+          null, // useContext()
+          null, // useContext()
+        ]);
+      }
+
+      // Note that this test is expected to only match the first two hooks
+      // because the 3rd and 4th hook are on the same line,
+      // and this type of source map doesn't have column numbers.
+      await noColumnTest(
+        './__source__/__compiled__/no-columns/ComponentWithMultipleHooksPerLine',
+      ); // simulated Webpack 'cheap-module-source-map'
     });
 
     // TODO Inline require (e.g. require("react").useState()) isn't supported yet.
@@ -287,6 +313,7 @@ describe('parseHookNames', () => {
       await test('./__source__/__compiled__/inline/InlineRequire'); // inline source map
       await test('./__source__/__compiled__/external/InlineRequire'); // external source map
       await test('./__source__/__compiled__/bundle', 'InlineRequire'); // bundle source map
+      await test('./__source__/__compiled__/no-columns/InlineRequire'); // simulated Webpack 'cheap-module-source-map'
     });
 
     it('should support sources that contain the string "sourceMappingURL="', async () => {
@@ -312,6 +339,9 @@ describe('parseHookNames', () => {
         './__source__/__compiled__/bundle',
         'ContainingStringSourceMappingURL',
       ); // bundle source map
+      await test(
+        './__source__/__compiled__/no-columns/ContainingStringSourceMappingURL',
+      ); // simulated Webpack 'cheap-module-source-map'
     });
   });
 });
diff --git a/packages/react-devtools-extensions/src/__tests__/updateMockSourceMaps.js b/packages/react-devtools-extensions/src/__tests__/updateMockSourceMaps.js
index 231bdee521266..6906abf52c927 100644
--- a/packages/react-devtools-extensions/src/__tests__/updateMockSourceMaps.js
+++ b/packages/react-devtools-extensions/src/__tests__/updateMockSourceMaps.js
@@ -14,18 +14,21 @@ const babel = require('rollup-plugin-babel');
 const commonjs = require('rollup-plugin-commonjs');
 const jsx = require('acorn-jsx');
 const rollupResolve = require('rollup-plugin-node-resolve');
+const {encode, decode} = require('sourcemap-codec');
 
 const sourceDir = resolve(__dirname, '__source__');
 const buildRoot = resolve(sourceDir, '__compiled__');
 const externalDir = resolve(buildRoot, 'external');
 const inlineDir = resolve(buildRoot, 'inline');
 const bundleDir = resolve(buildRoot, 'bundle');
+const noColumnsDir = resolve(buildRoot, 'no-columns');
 
 // Remove previous builds
 emptyDirSync(buildRoot);
 mkdirSync(externalDir);
 mkdirSync(inlineDir);
 mkdirSync(bundleDir);
+mkdirSync(noColumnsDir);
 
 function compile(fileName) {
   const code = readFileSync(resolve(sourceDir, fileName), 'utf8');
@@ -60,6 +63,25 @@ function compile(fileName) {
     'utf8',
   );
 
+  // Strip column numbers from source map to mimic Webpack 'cheap-module-source-map'
+  // The mappings field represents a list of integer arrays.
+  // Each array defines a pair of corresponding file locations, one in the generated code and one in the original.
+  // Each array has also been encoded first as VLQs (variable-length quantities)
+  // and then as base64 because this makes them more compact overall.
+  // https://docs.google.com/document/d/1U1RGAehQwRypUTovF1KRlpiOFze0b-_2gc6fAH0KY0k/view#
+  const decodedMappings = decode(sourceMap.mappings).map(entries =>
+    entries.map(entry => {
+      if (entry.length === 0) {
+        return entry;
+      }
+
+      // Each non-empty segment has the following components:
+      // generated code column, source index, source code line, source code column, and (optional) name index
+      return [...entry.slice(0, 3), 0, ...entry.slice(4)];
+    }),
+  );
+  const encodedMappings = encode(decodedMappings);
+
   // Generate compiled output with external inline base64 source maps
   writeFileSync(
     resolve(inlineDir, fileName),
@@ -68,6 +90,20 @@ function compile(fileName) {
       btoa(JSON.stringify(sourceMap)),
     'utf8',
   );
+
+  // Generate compiled output with external inline base64 source maps without column numbers
+  writeFileSync(
+    resolve(noColumnsDir, fileName),
+    transformed.code +
+      '\n//# sourceMappingURL=data:application/json;charset=utf-8;base64,' +
+      btoa(
+        JSON.stringify({
+          ...sourceMap,
+          mappings: encodedMappings,
+        }),
+      ),
+    'utf8',
+  );
 }
 
 async function bundle() {
diff --git a/packages/react-devtools-extensions/src/astUtils.js b/packages/react-devtools-extensions/src/astUtils.js
index 879f17ae18055..87a4f47dcaeab 100644
--- a/packages/react-devtools-extensions/src/astUtils.js
+++ b/packages/react-devtools-extensions/src/astUtils.js
@@ -32,7 +32,7 @@ const AST_NODE_TYPES = Object.freeze({
 function checkNodeLocation(
   path: NodePath,
   line: number,
-  column: number,
+  column?: number | null = null,
 ): boolean {
   const {start, end} = path.node.loc;
 
@@ -40,22 +40,24 @@ function checkNodeLocation(
     return false;
   }
 
-  // Column numbers are representated differently between tools/engines.
-  // Error.prototype.stack columns are 1-based (like most IDEs) but ASTs are 0-based.
-  //
-  // In practice this will probably never matter,
-  // because this code matches the 1-based Error stack location for the hook Identifier (e.g. useState)
-  // with the larger 0-based VariableDeclarator (e.g. [foo, setFoo] = useState())
-  // so the ranges should always overlap.
-  //
-  // For more info see https://github.com/facebook/react/pull/21833#discussion_r666831276
-  column -= 1;
-
-  if (
-    (line === start.line && column < start.column) ||
-    (line === end.line && column > end.column)
-  ) {
-    return false;
+  if (column !== null) {
+    // Column numbers are representated differently between tools/engines.
+    // Error.prototype.stack columns are 1-based (like most IDEs) but ASTs are 0-based.
+    //
+    // In practice this will probably never matter,
+    // because this code matches the 1-based Error stack location for the hook Identifier (e.g. useState)
+    // with the larger 0-based VariableDeclarator (e.g. [foo, setFoo] = useState())
+    // so the ranges should always overlap.
+    //
+    // For more info see https://github.com/facebook/react/pull/21833#discussion_r666831276
+    column -= 1;
+
+    if (
+      (line === start.line && column < start.column) ||
+      (line === end.line && column > end.column)
+    ) {
+      return false;
+    }
   }
 
   return true;
@@ -122,15 +124,35 @@ export function getHookName(
 ): string | null {
   const hooksFromAST = getPotentialHookDeclarationsFromAST(originalSourceAST);
 
-  const potentialReactHookASTNode = hooksFromAST.find(node => {
-    const nodeLocationCheck = checkNodeLocation(
-      node,
-      originalSourceLineNumber,
-      originalSourceColumnNumber,
-    );
-    const hookDeclaractionCheck = isConfirmedHookDeclaration(node);
-    return nodeLocationCheck && hookDeclaractionCheck;
-  });
+  let potentialReactHookASTNode = null;
+  if (originalSourceColumnNumber === 0) {
+    // This most likely indicates a source map type like 'cheap-module-source-map'
+    // that intentionally drops column numbers for compilation speed in DEV builds.
+    // In this case, we can assume there's probably only one hook per line (true in most cases)
+    // and just fail if we find more than one match.
+    const matchingNodes = hooksFromAST.filter(node => {
+      const nodeLocationCheck = checkNodeLocation(
+        node,
+        originalSourceLineNumber,
+      );
+      const hookDeclaractionCheck = isConfirmedHookDeclaration(node);
+      return nodeLocationCheck && hookDeclaractionCheck;
+    });
+
+    if (matchingNodes.length === 1) {
+      potentialReactHookASTNode = matchingNodes[0];
+    }
+  } else {
+    potentialReactHookASTNode = hooksFromAST.find(node => {
+      const nodeLocationCheck = checkNodeLocation(
+        node,
+        originalSourceLineNumber,
+        originalSourceColumnNumber,
+      );
+      const hookDeclaractionCheck = isConfirmedHookDeclaration(node);
+      return nodeLocationCheck && hookDeclaractionCheck;
+    });
+  }
 
   if (!potentialReactHookASTNode) {
     return null;
diff --git a/packages/react-devtools-extensions/src/parseHookNames.js b/packages/react-devtools-extensions/src/parseHookNames.js
index be6deb71f554a..218bd596d03a7 100644
--- a/packages/react-devtools-extensions/src/parseHookNames.js
+++ b/packages/react-devtools-extensions/src/parseHookNames.js
@@ -350,7 +350,7 @@ function fetchFile(url: string): Promise<string> {
       },
       error => {
         if (__DEBUG__) {
-          console.log(`fetchFile() Could not fetch file "${error.message}"`);
+          console.log(`fetchFile() Could not fetch file: ${error.message}`);
         }
         reject(null);
       },
diff --git a/yarn.lock b/yarn.lock
index 3332b21474771..c0bddfe82c64e 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -13047,7 +13047,7 @@ source-map@^0.8.0-beta.0:
   dependencies:
     whatwg-url "^7.0.0"
 
-sourcemap-codec@^1.4.1, sourcemap-codec@^1.4.4:
+sourcemap-codec@^1.4.1, sourcemap-codec@^1.4.4, sourcemap-codec@^1.4.8:
   version "1.4.8"
   resolved "https://registry.yarnpkg.com/sourcemap-codec/-/sourcemap-codec-1.4.8.tgz#ea804bd94857402e6992d05a38ef1ae35a9ab4c4"
   integrity sha512-9NykojV5Uih4lgo5So5dtw+f0JgJX30KCNI8gwhz2J9A15wD0Ml6tjHKwf6fTSa6fAdVBdZeNOs9eJ71qCk8vA==