refactor: rename 'ExactValidator' validator to 'NoExtraPropsValidator'

The name was not correct, since the validator does just check that
no extra props are passed. The 'prop-tpyes' 'PropTypes.exact' validator
cannot be used on the root object assigned to a component, so it is of
no use to us in this case. Closes #49.

Author: matteocng

src/__tests__/types/propTypes.js

@@ -5,7 +5,7 @@ import test from 'ava' // eslint-disable-line import/no-extraneous-dependencies
 
 import MakeConsoleHook, { ConsoleOutput } from '../internals/ConsoleHook'
 import FlagIconFactory from '../../'
-import { AddExactValidator } from '../../functions/propTypes'
+import { AddNoExtraPropsValidator } from '../../functions/propTypes'
 
 /**
  * TODO: remove 'ConsoleHook' as soon as possible. SEE: "Add ability to throw
@@ -67,19 +67,36 @@ test('FlagIconOptionsType', (t: *) => {
   consoleHook.detach()
 })
 
-test('exact validator', (t: *) => {
+test('No extra props validator', (t: *) => {
   const consoleHook = MakeConsoleHook({ outputType: ConsoleOutput.error })
-  const propsTypes = AddExactValidator({
+  const propsTypes = AddNoExtraPropsValidator({
     code: PropTypes.string.isRequired,
   })
 
   PropTypes.checkPropTypes(
     propsTypes,
     { code: 'it', additional: 'lorem' },
     'key',
-    'Exact validator test',
+    'No extra props validator test',
   )
+
   t.truthy(consoleHook.flushLog())
 
-  consoleHook.detach()
+  // `AddNoExtraPropsValidator` is not an `exact` validator and doesn't check if
+  // a prop was not passed. It triggers an error if it finds undeclared, extra props.
+  // This means the user has to set`.isRequired` to check that a prop is required.
+  const propsTypesTwo = AddNoExtraPropsValidator({
+    lorem: PropTypes.string,
+    ipsum: PropTypes.bool,
+  })
+
+  PropTypes.checkPropTypes(
+    propsTypesTwo,
+    {},
+    'key',
+    'No extra props validator test',
+  )
+
+  // No errors because there are no `extra` props.
+  t.falsy(consoleHook.flushLog())
 })

src/functions/propTypes.js

@@ -66,7 +66,7 @@ export const AddThemeStylesValidator = (
  *
  * SEE: https://github.com/reactjs/prop-types
  */
-const fnExactValidator = (
+const fnNoExtraPropsValidator = (
   // prop-types Object supplied by the user. i.e {lorem: PropTypes.string}
   propsObject: PropsTypeObjectType,
   // prop-values Object supplied by the user. i.e {lorem: 'ipsum'}
@@ -90,29 +90,34 @@ const fnExactValidator = (
 
 /**
  * Adds a 'custom validator' function to `obj`; this function makes sure that any
- * 'prop' passed by the user at runtime exists in `obj`, otherwise it throws an Error.
- * `obj` is a 'props' object, the one you would assign to `SomeComponent.propTypes`
+ * 'prop' passed by the user at runtime exists as a key in `obj`, otherwise it throws
+ * an Error. `obj` is a 'props' object, the one you would assign to `SomeComponent.propTypes`
  * or pass to `PropTypes.checkPropTypes()`. i.e {lorem: PropTypes.string}
  *
- * We use bind() to make a new `fnExactValidator` function with the first argument
+ * We use bind() to make a new `fnNoExtraPropsValidator` function with the first argument
  * set as: `obj`. We need to do this because `prop-types` doesn't pass this object
- * to 'custom validator' functions such as `fnExactValidator`.
+ * to 'custom validator' functions such as `fnNoExtraPropsValidator`.
+ *
+ * This type of validation is NOT the runtime equivalent to Flow's 'exact object
+ * types', since we don't check if any required `prop-types` props have been supplied
+ * or not, relying on the user to have specified an appropriate `isRequired` prop-type
+ * for those.
  *
- * This type of validation is the runtime equivalent to Flow's 'exact object types'.
  * SEE: https://flow.org/en/docs/types/objects/#toc-exact-object-types
  */
 // eslint-disable-next-line import/prefer-default-export, max-len
-export const AddExactValidator = (
+export const AddNoExtraPropsValidator = (
   obj: PropsTypeObjectType,
 ): PropsTypeObjectType => {
-  const validatorKeyName = '__exact__'
+  const validatorKeyName = '__no__extra__props__validator___'
   if (Object.prototype.hasOwnProperty.call(obj, validatorKeyName)) {
-    // TODO: print a message or throw when not in production?
-    return obj // The custom validator is already 'installed'.
+    // The custom validator is already 'installed', or the user has managed to
+    // somehow use `validatorKeyName`.
+    return obj
   }
 
   return {
     ...obj,
-    [validatorKeyName]: fnExactValidator.bind(this, obj),
+    [validatorKeyName]: fnNoExtraPropsValidator.bind(this, obj),
   }
 }

src/types/propTypes.js

@@ -2,7 +2,7 @@
 import PropTypes from 'prop-types'
 import { getRotates, getFlips, getSizes } from '../functions/props'
 import {
-  AddExactValidator,
+  AddNoExtraPropsValidator,
   AddThemeStylesValidator,
 } from '../functions/propTypes'
 import type { FlagIconCodeType, PropsTypeObjectType } from '../types/flow'
@@ -49,7 +49,8 @@ const makeFlagIconPropsTypeObject = <T>(
 export const MakeFlagIconPropsType = <T>(
   codes: MaybeFlagIconCodeType<T>[],
   // eslint-disable-next-line arrow-body-style
-): PropsTypeObjectType => AddExactValidator(makeFlagIconPropsTypeObject(codes))
+): PropsTypeObjectType =>
+  AddNoExtraPropsValidator(makeFlagIconPropsTypeObject(codes))
 
 const flagIconOptionsType = {
   customCodes: PropTypes.object,
@@ -58,4 +59,4 @@ const flagIconOptionsType = {
 }
 
 export const MakeFlagIconOptionsPropType = (): PropsTypeObjectType =>
-  AddExactValidator(AddThemeStylesValidator(flagIconOptionsType))
+  AddNoExtraPropsValidator(AddThemeStylesValidator(flagIconOptionsType))