feat: support cy.not previous command (#76)

* feat: support cy.not previous command

* update Cy v11

README.md

@@ -18,7 +18,7 @@ Tested with `cy.get`, `cy.contains`, `cy.find`, `.then`, `.within` commands in C
 
 ## ⚠️ Warning
 
-In general, Cypress team considers [conditional testing an anti-pattern](https://on.cypress.io/conditional-testing). Thus `cypress-if` should be used only if the test really cannot deterministically execute its steps.
+In general, Cypress team considers [conditional testing an anti-pattern](https://on.cypress.io/conditional-testing). Thus `cypress-if` should be used only if the test really cannot deterministically execute its steps. You can also read my [conditional testing](https://glebbahmutov.com/cypress-examples/recipes/conditional-testing.html) examples.
 
 ## No xpath support
 

cypress/e2e/exists.cy.js

@@ -58,3 +58,21 @@ it('uses exists as an alias to exist', () => {
   cy.get('@if').should('have.been.calledOnce')
   cy.get('@else').should('not.have.been.called')
 })
+
+it('supports cy.not', () => {
+  cy.log('**IF path**')
+  cy.get('#fruits li')
+    .not(':odd')
+    .if('exists')
+    .log('found even')
+    .else()
+    .raise('it is odd')
+
+  cy.log('**ELSE path**')
+  cy.get('#fruits li')
+    .not('li')
+    .if('exists')
+    .raise('cy.not is not supported')
+    .else()
+    .log('cy.not is supported')
+})

src/index-v11.js

@@ -289,6 +289,29 @@ Cypress.Commands.overwrite(
   },
 )
 
+Cypress.Commands.overwrite('not', function (notCommand, prevSubject, selector) {
+  debug('cy.not args', { prevSubject, selector })
+
+  const cmd = cy.state('current')
+  debug(cmd)
+  const next = cmd.attributes.next
+
+  if (next && next.attributes.name === 'if') {
+    // disable the built-in assertion
+    return notCommand(prevSubject, selector).then(
+      (getResult) => {
+        debug('internal cy.not result', getResult)
+        return getResult
+      },
+      (noResult) => {
+        debug('no cy.not result', noResult)
+      },
+    )
+  }
+
+  return notCommand(prevSubject, selector, text, options)
+})
+
 Cypress.Commands.overwrite(
   'find',
   function (find, prevSubject, selector, options) {

src/index.js

@@ -359,4 +359,27 @@ if (major < 12) {
     )
     throw e
   })
+
+  Cypress.Commands.overwriteQuery('not', function (notCommand, selector) {
+    debug('cy.not args', { selector })
+
+    const cmd = cy.state('current')
+    debug(cmd)
+    const next = cmd.attributes.next
+    const innerFn = notCommand.call(this, selector)
+
+    if (isIfCommand(next)) {
+      // disable the built-in assertion
+      return (subject) => {
+        const res = innerFn(subject)
+        if (res.length) {
+          debug('internal not result', res)
+          return res
+        }
+        debug('no not result')
+      }
+    }
+
+    return (subject) => innerFn(subject)
+  })
 }