{"record":{"id":"f1cd26af9e76cacc","repo":"jaredpalmer/formik","slug":"warning-formik-called-handlername-but-you","errorCode":null,"errorMessage":"Warning: Formik called \\`${handlerName}\\`, but you forgot to pass an \\`id\\` or \\`name\\` attribute to your input:\\n    ${htmlContent}\\n    Formik cannot determine which value to update. For more info see https://formik.org/docs/api/formik#${documentationAnchorLink}\\n  ","messagePattern":"Warning: Formik called \\\\`(.+?)\\\\`, but you forgot to pass an \\\\`id\\\\` or \\\\`name\\\\` attribute to your input:\\\\n    (.+?)\\\\n    Formik cannot determine which value to update\\. For more info see https://formik\\.org/docs/api/formik#(.+?)\\\\n  ","errorType":"console","errorClass":null,"httpStatus":null,"severity":"warning","filePath":"packages/formik/src/Formik.tsx","lineNumber":1051,"sourceCode":"            )\n          : !isEmptyChildren(children)\n          ? React.Children.only(children)\n          : null\n        : null}\n    </FormikProvider>\n  );\n}\n\nfunction warnAboutMissingIdentifier({\n  htmlContent,\n  documentationAnchorLink,\n  handlerName,\n}: {\n  htmlContent: string;\n  documentationAnchorLink: string;\n  handlerName: string;\n}) {\n  console.warn(\n    `Warning: Formik called \\`${handlerName}\\`, but you forgot to pass an \\`id\\` or \\`name\\` attribute to your input:\n    ${htmlContent}\n    Formik cannot determine which value to update. For more info see https://formik.org/docs/api/formik#${documentationAnchorLink}\n  `\n  );\n}\n\n/**\n * Transform Yup ValidationError to a more usable object\n */\nexport function yupToFormErrors<Values>(yupError: any): FormikErrors<Values> {\n  let errors: FormikErrors<Values> = {};\n  if (yupError.inner) {\n    if (yupError.inner.length === 0) {\n      return setIn(errors, yupError.path, yupError.message);\n    }\n    for (let err of yupError.inner) {\n      if (!getIn(errors, err.path)) {","sourceCodeStart":1033,"sourceCodeEnd":1069,"githubUrl":"https://github.com/jaredpalmer/formik/blob/91475adbf33579561e580eceea0c031f4ec2e992/packages/formik/src/Formik.tsx#L1033-L1069","documentation":"A `<Field>`/`<FastField>`-rendered input fired change or blur, and Formik's `handleChange`/`handleBlur` received an event whose target has neither `id` nor `name`. Without one of those attributes Formik cannot map the event to a key in `values`, so it warns (dev only) and the value is silently not updated.","triggerScenarios":"`<Field>` without `name` (e.g. `<Field component={CustomInput} />` where the custom component forgets to spread `field` onto the underlying `<input>`), passing `handleChange` to a non-standard component that swallows name, or manually calling `handleChange({ target: {} })`.","commonSituations":"Custom input components that don't spread `{...field}` or `{...props}`; copy-pasted `<input onChange={handleChange} />` without name; using handleBlur/handleChange with UI libraries requiring explicit `name` props.","solutions":["Ensure every input wired to Formik has a `name` (or `id`) attribute matching a key in initial values: `<Field name=\"email\" ... />`.","In custom components, spread Formik's field props: `<input {...field} {...props} />`.","When calling handlers manually, pass a React SyntheticEvent whose target has a name: `handleChange({ target: { name: 'email', value } } as any)`."],"exampleFix":"// before\n<Field component={() => <input onChange={handleChange} />} />\n// after\n<Field name=\"email\" component={() => <input name=\"email\" onChange={handleChange} />} />\n// or in custom components:\nconst MyInput = ({ field, form, ...props }) => <input {...field} {...props} />;","handlingStrategy":"validation","validationCode":"// lint/dev check: every Field must have a name\n// react/jsx-props rule or a tiny wrapper\nconst SafeField = (props) => {\n  if (process.env.NODE_ENV !== 'production' && !props.name) {\n    console.error('<Field> requires a name');\n  }\n  return <Field {...props} />;\n};","typeGuard":"const hasIdentifier = (el: HTMLInputElement | null): el is HTMLInputElement & { name: string } =>\n  !!el && (!!el.name || !!el.id);\n\n// in custom components spread field so name/onChange/id propagate","tryCatchPattern":"// when invoking handlers manually, always include name\nhandleChange({\n  target: { name: 'email', value: e.target.value },\n} as React.ChangeEvent<HTMLInputElement>);","preventionTips":["Always spread {...field} in custom input components","Give every input a name matching a key in initialValues","Type initial values and values passed to handlers so missing keys surface at compile time"],"tags":["formik","handlechange","handleblur","missing-name","field"],"backgroundTag":"missing-form-field-name","analyzedSha":"91475adbf33579561e580eceea0c031f4ec2e992","analyzedAt":"2026-08-27T12:26:57.937Z","schemaVersion":2},"datasetVersion":"2026-08-27T13:17:12.746Z"}