fix(bug): indeterminate checkbox state doesn't get changed (#21665)

packages/driver/cypress/e2e/commands/actions/check.cy.js

@@ -71,6 +71,21 @@ describe('src/cy/commands/actions/check', () => {
       })
     })
 
+    // https://github.com/cypress-io/cypress/issues/19098
+    it('removes indeterminate prop when checkbox is checked', () => {
+      const intermediateCheckbox = $(`<input type='checkbox' name="indeterminate">`)
+
+      intermediateCheckbox.prop('indeterminate', true)
+
+      $('body').append(intermediateCheckbox)
+
+      cy.get(':checkbox[name=\'indeterminate\']').check().then(($checkbox) => {
+        const hasIndeterminate = $checkbox.prop('indeterminate')
+
+        expect(hasIndeterminate).to.be.false
+      })
+    })
+
     it('is a noop if already checked', () => {
       const checkbox = ':checkbox[name=\'colors\'][value=\'blue\']'
 
@@ -839,6 +854,21 @@ describe('src/cy/commands/actions/check', () => {
       })
     })
 
+    // https://github.com/cypress-io/cypress/issues/19098
+    it('removes indeterminate prop when checkbox is unchecked', () => {
+      const indeterminateCheckbox = $(`<input type='checkbox' name="indeterminate">`)
+
+      indeterminateCheckbox.prop('indeterminate', true)
+
+      $('body').append(indeterminateCheckbox)
+
+      cy.get(':checkbox[name=\'indeterminate\']').uncheck().then(($checkbox) => {
+        const hasIndeterminate = $checkbox.prop('indeterminate')
+
+        expect(hasIndeterminate).to.be.false
+      })
+    })
+
     it('unchecks a checkbox', () => {
       cy.get('[name=birds][value=cockatoo]').uncheck().then(($checkbox) => {
         expect($checkbox).not.to.be.checked

packages/driver/src/cy/commands/actions/check.ts

@@ -113,6 +113,13 @@ const checkOrUncheck = (Cypress, cy, type, subject, values: any[] = [], userOpti
           cy.ensureVisibility($el, options._log)
         }
 
+        // if the checkbox is in an indeterminate state, checking or unchecking should set the
+        // prop to false to move it into a "determinate" state
+        // https://github.com/cypress-io/cypress/issues/19098
+        if ($el.prop('indeterminate')) {
+          $el.prop('indeterminate', false)
+        }
+
         if (options._log) {
           const inputType = $el.is(':radio') ? 'radio' : 'checkbox'