feat: add impl and tests

README.md

@@ -1,5 +1,5 @@
 # @semrel-extra/npm
-Drop-in-repl npm plugin to handle `npm-whoami` throttling issue for monorepos: https://github.com/semantic-release/npm/issues/414
+Drop-in-repl for standard npm plugin to handle `npm-whoami` throttling issue for monorepos: [semantic-release/npm/issues/414](https://github.com/semantic-release/npm/issues/414)
 
 ### Install
 ```shell

package.json

@@ -6,6 +6,11 @@
   "scripts": {
     "test": "uvu ./src/test/*"
   },
+  "files": [
+    "src/main",
+    "LICENSE",
+    "README.md"
+  ],
   "repository": {
     "type": "git",
     "url": "git+https://github.com/semrel-extra/npm.git"

src/main/js/index.js

@@ -0,0 +1,22 @@
+const plugin = require('@semantic-release/npm')
+
+let verified
+let result
+
+async function verifyConditionsHooked(...args) {
+  if (verified) {
+    return result
+  }
+
+  return plugin.verifyConditions(...args).then(r => {
+    result = r
+    verified = true
+  })
+}
+
+verifyConditionsHooked._reset = () => {
+  result = undefined
+  verified = undefined
+}
+
+module.exports = { ...plugin, verifyConditions: verifyConditionsHooked }

src/test/js/index.js

@@ -0,0 +1,36 @@
+const sinon = require('sinon')
+const { test } = require('uvu')
+const assert = require('uvu/assert')
+const plugin = require('../../main/js')
+const realNpmPlugin = require('@semantic-release/npm')
+
+test('prepare, publish, addChannel are re-exported as is', () => {
+  assert.is(realNpmPlugin.addChannel, plugin.addChannel)
+  assert.is(realNpmPlugin.publish, plugin.publish)
+  assert.is(realNpmPlugin.prepare, plugin.prepare)
+})
+
+test('verifyConditions passes args down to `semrel/npm`', async () => {
+  const mock = sinon.mock(realNpmPlugin)
+  mock.expects('verifyConditions').once().withArgs('test').returns(Promise.resolve())
+
+  await plugin.verifyConditions('test')
+
+  mock.verify()
+  mock.restore()
+  plugin.verifyConditions._reset()
+})
+
+test('prevents multiple `verifyConditions` invocations', async () => {
+  const mock = sinon.mock(realNpmPlugin)
+  mock.expects('verifyConditions').once().withArgs('test').returns(Promise.resolve())
+
+  await plugin.verifyConditions('test')
+  await plugin.verifyConditions('test')
+
+  mock.verify()
+  mock.restore()
+  plugin.verifyConditions._reset()
+})
+
+test.run()