Handle invisible characters in forms

src/CONST.ts

@@ -1359,6 +1359,10 @@ const CONST = {
         ILLEGAL_FILENAME_CHARACTERS: /\/|<|>|\*|"|:|\?|\\|\|/g,
 
         ENCODE_PERCENT_CHARACTER: /%(25)+/g,
+
+        INVISIBLE_CHARACTERS_GROUPS: /[\p{C}\p{Z}]/gu,
+
+        OTHER_INVISIBLE_CHARACTERS: /[\u3164]/g,
     },
 
     PRONOUNS: {

src/components/Form.js

@@ -6,6 +6,7 @@ import {withOnyx} from 'react-native-onyx';
 import _ from 'underscore';
 import compose from '@libs/compose';
 import * as ErrorUtils from '@libs/ErrorUtils';
+import removeInvisibleCharacters from '@libs/removeInvisibleCharacters';
 import Visibility from '@libs/Visibility';
 import stylePropTypes from '@styles/stylePropTypes';
 import styles from '@styles/styles';
@@ -120,20 +121,32 @@ function Form(props) {
 
     const hasServerError = useMemo(() => Boolean(props.formState) && !_.isEmpty(props.formState.errors), [props.formState]);
 
+    /**
+     * This function is used to remove invisible characters from strings before validation and submission.
+     *
+     * @param {Object} values - An object containing the value of each inputID, e.g. {inputID1: value1, inputID2: value2}
+     * @returns {Object} - An object containing the processed values of each inputID
+     */
+    const prepareValues = useCallback((values) => {
+        const trimmedStringValues = {};
+        _.each(values, (inputValue, inputID) => {
+            if (_.isString(inputValue)) {
+                trimmedStringValues[inputID] = removeInvisibleCharacters(inputValue);
+            } else {
+                trimmedStringValues[inputID] = inputValue;
+            }
+        });
+        return trimmedStringValues;
+    }, []);
+
     /**
      * @param {Object} values - An object containing the value of each inputID, e.g. {inputID1: value1, inputID2: value2}
      * @returns {Object} - An object containing the errors for each inputID, e.g. {inputID1: error1, inputID2: error2}
      */
     const onValidate = useCallback(
         (values, shouldClearServerError = true) => {
-            const trimmedStringValues = {};
-            _.each(values, (inputValue, inputID) => {
-                if (_.isString(inputValue)) {
-                    trimmedStringValues[inputID] = inputValue.trim();
-                } else {
-                    trimmedStringValues[inputID] = inputValue;
-                }
-            });
+            // Trim all string values
+            const trimmedStringValues = prepareValues(values);
 
             if (shouldClearServerError) {
                 FormActions.setErrors(props.formID, null);
@@ -191,7 +204,7 @@ function Form(props) {
 
             return touchedInputErrors;
         },
-        [errors, touchedInputs, props.formID, validate],
+        [prepareValues, props.formID, validate, errors],
     );
 
     useEffect(() => {
@@ -228,11 +241,14 @@ function Form(props) {
             return;
         }
 
+        // Trim all string values
+        const trimmedStringValues = prepareValues(inputValues);
+
         // Touches all form inputs so we can validate the entire form
         _.each(inputRefs.current, (inputRef, inputID) => (touchedInputs.current[inputID] = true));
 
         // Validate form and return early if any errors are found
-        if (!_.isEmpty(onValidate(inputValues))) {
+        if (!_.isEmpty(onValidate(trimmedStringValues))) {
             return;
         }
 
@@ -242,8 +258,8 @@ function Form(props) {
         }
 
         // Call submit handler
-        onSubmit(inputValues);
-    }, [props.formState, onSubmit, inputRefs, inputValues, onValidate, touchedInputs, props.network.isOffline, props.enabledWhenOffline]);
+        onSubmit(trimmedStringValues);
+    }, [props.formState.isLoading, props.network.isOffline, props.enabledWhenOffline, prepareValues, inputValues, onValidate, onSubmit]);
 
     /**
      * Loops over Form's children and automatically supplies Form props to them

src/components/Form/FormProvider.js

@@ -6,6 +6,7 @@ import _ from 'underscore';
 import networkPropTypes from '@components/networkPropTypes';
 import {withNetwork} from '@components/OnyxProvider';
 import compose from '@libs/compose';
+import removeInvisibleCharacters from '@libs/removeInvisibleCharacters';
 import Visibility from '@libs/Visibility';
 import stylePropTypes from '@styles/stylePropTypes';
 import * as FormActions from '@userActions/FormActions';
@@ -106,16 +107,27 @@ function FormProvider({validate, formID, shouldValidateOnBlur, shouldValidateOnC
     const [errors, setErrors] = useState({});
     const hasServerError = useMemo(() => Boolean(formState) && !_.isEmpty(formState.errors), [formState]);
 
+    /**
+     * This function is used to remove invisible characters from strings before validation and submission.
+     *
+     * @param {Object} values - An object containing the value of each inputID, e.g. {inputID1: value1, inputID2: value2}
+     * @returns {Object} - An object containing the processed values of each inputID
+     */
+    const prepareValues = useCallback((values) => {
+        const trimmedStringValues = {};
+        _.each(values, (inputValue, inputID) => {
+            if (_.isString(inputValue)) {
+                trimmedStringValues[inputID] = removeInvisibleCharacters(inputValue);
+            } else {
+                trimmedStringValues[inputID] = inputValue;
+            }
+        });
+        return trimmedStringValues;
+    }, []);
+
     const onValidate = useCallback(
         (values, shouldClearServerError = true) => {
-            const trimmedStringValues = {};
-            _.each(values, (inputValue, inputID) => {
-                if (_.isString(inputValue)) {
-                    trimmedStringValues[inputID] = inputValue.trim();
-                } else {
-                    trimmedStringValues[inputID] = inputValue;
-                }
-            });
+            const trimmedStringValues = prepareValues(values);
 
             if (shouldClearServerError) {
                 FormActions.setErrors(formID, null);
@@ -167,7 +179,7 @@ function FormProvider({validate, formID, shouldValidateOnBlur, shouldValidateOnC
 
             return touchedInputErrors;
         },
-        [errors, formID, validate],
+        [errors, formID, prepareValues, validate],
     );
 
     /**
@@ -186,11 +198,14 @@ function FormProvider({validate, formID, shouldValidateOnBlur, shouldValidateOnC
             return;
         }
 
+        // Prepare values before submitting
+        const trimmedStringValues = prepareValues(inputValues);
+
         // Touches all form inputs so we can validate the entire form
         _.each(inputRefs.current, (inputRef, inputID) => (touchedInputs.current[inputID] = true));
 
         // Validate form and return early if any errors are found
-        if (!_.isEmpty(onValidate(inputValues))) {
+        if (!_.isEmpty(onValidate(trimmedStringValues))) {
             return;
         }
 
@@ -199,8 +214,8 @@ function FormProvider({validate, formID, shouldValidateOnBlur, shouldValidateOnC
             return;
         }
 
-        onSubmit(inputValues);
-    }, [enabledWhenOffline, formState.isLoading, inputValues, network.isOffline, onSubmit, onValidate]);
+        onSubmit(trimmedStringValues);
+    }, [enabledWhenOffline, formState.isLoading, inputValues, network.isOffline, onSubmit, onValidate, prepareValues]);
 
     const registerInput = useCallback(
         (inputID, propsToParse = {}) => {

src/libs/ValidationUtils.ts

@@ -8,6 +8,7 @@ import CONST from '@src/CONST';
 import {Report} from '@src/types/onyx';
 import * as OnyxCommon from '@src/types/onyx/OnyxCommon';
 import * as CardUtils from './CardUtils';
+import isEmptyString from './isEmptyString';
 import * as LoginUtils from './LoginUtils';
 
 /**
@@ -73,7 +74,7 @@ function isValidPastDate(date: string | Date): boolean {
  */
 function isRequiredFulfilled(value: string | Date | unknown[] | Record<string, unknown>): boolean {
     if (typeof value === 'string') {
-        return value.trim().length > 0;
+        return !isEmptyString(value);
     }
 
     if (isDate(value)) {

src/libs/isEmptyString.ts

@@ -0,0 +1,19 @@
+import CONST from '@src/CONST';
+
+/**
+ *  Check if the string would be empty if all invisible characters were removed.
+ */
+function isEmptyString(value: string): boolean {
+    // \p{C} matches all 'Other' characters
+    // \p{Z} matches all separators (spaces etc.)
+    // Source: http://www.unicode.org/reports/tr18/#General_Category_Property
+    let transformed = value.replace(CONST.REGEX.INVISIBLE_CHARACTERS_GROUPS, '');
+
+    // Remove other invisible characters that are not in the above unicode categories
+    transformed = transformed.replace(CONST.REGEX.OTHER_INVISIBLE_CHARACTERS, '');
+
+    // Check if after removing invisible characters the string is empty
+    return transformed === '';
+}
+
+export default isEmptyString;

src/libs/removeInvisibleCharacters.ts

@@ -0,0 +1,33 @@
+import isEmptyString from './isEmptyString';
+
+/**
+ *  Remove invisible characters from a string except for spaces and format characters for emoji, and trim it.
+ */
+function removeInvisibleCharacters(value: string): string {
+    let result = value;
+
+    // Remove spaces:
+    // - \u200B: zero-width space
+    // - \u00A0: non-breaking space
+    // - \u2060: word joiner
+    result = result.replace(/[\u200B\u00A0\u2060]/g, '');
+
+    // Remove all characters from the 'Other' (C) category except for format characters (Cf)
+    // because some of them are used for emojis
+    result = result.replace(/[\p{Cc}\p{Cs}\p{Co}\p{Cn}]/gu, '');
+
+    // Remove characters from the (Cf) category that are not used for emojis
+    result = result.replace(/[\u200E-\u200F]/g, '');
+
+    // Remove all characters from the 'Separator' (Z) category except for Space Separator (Zs)
+    result = result.replace(/[\p{Zl}\p{Zp}]/gu, '');
+
+    // If the result consist of only invisible characters, return an empty string
+    if (isEmptyString(result)) {
+        return '';
+    }
+
+    return result.trim();
+}
+
+export default removeInvisibleCharacters;

src/pages/workspace/WorkspaceSettingsPage.js

@@ -19,6 +19,7 @@ import compose from '@libs/compose';
 import Navigation from '@libs/Navigation/Navigation';
 import * as ReportUtils from '@libs/ReportUtils';
 import * as UserUtils from '@libs/UserUtils';
+import * as ValidationUtils from '@libs/ValidationUtils';
 import styles from '@styles/styles';
 import * as Policy from '@userActions/Policy';
 import CONST from '@src/CONST';
@@ -76,7 +77,7 @@ function WorkspaceSettingsPage({policy, currencyList, windowWidth, route}) {
         const errors = {};
         const name = values.name.trim();
 
-        if (!name || !name.length) {
+        if (!ValidationUtils.isRequiredFulfilled(name)) {
             errors.name = 'workspace.editor.nameIsRequiredError';
         } else if ([...name].length > CONST.WORKSPACE_NAME_CHARACTER_LIMIT) {
             // Uses the spread syntax to count the number of Unicode code points instead of the number of UTF-16

src/stories/Form.stories.js

@@ -10,6 +10,7 @@ import StatePicker from '@components/StatePicker';
 import Text from '@components/Text';
 import TextInput from '@components/TextInput';
 import NetworkConnection from '@libs/NetworkConnection';
+import * as ValidationUtils from '@libs/ValidationUtils';
 import styles from '@styles/styles';
 import * as FormActions from '@userActions/FormActions';
 import CONST from '@src/CONST';
@@ -177,28 +178,28 @@ const defaultArgs = {
     submitButtonText: 'Submit',
     validate: (values) => {
         const errors = {};
-        if (!values.routingNumber) {
+        if (!ValidationUtils.isRequiredFulfilled(values.routingNumber)) {
             errors.routingNumber = 'Please enter a routing number';
         }
-        if (!values.accountNumber) {
+        if (!ValidationUtils.isRequiredFulfilled(values.accountNumber)) {
             errors.accountNumber = 'Please enter an account number';
         }
-        if (!values.street) {
+        if (!ValidationUtils.isRequiredFulfilled(values.street)) {
             errors.street = 'Please enter an address';
         }
-        if (!values.dob) {
+        if (!ValidationUtils.isRequiredFulfilled(values.dob)) {
             errors.dob = 'Please enter your date of birth';
         }
-        if (!values.pickFruit) {
+        if (!ValidationUtils.isRequiredFulfilled(values.pickFruit)) {
             errors.pickFruit = 'Please select a fruit';
         }
-        if (!values.pickAnotherFruit) {
+        if (!ValidationUtils.isRequiredFulfilled(values.pickAnotherFruit)) {
             errors.pickAnotherFruit = 'Please select a fruit';
         }
-        if (!values.state) {
+        if (!ValidationUtils.isRequiredFulfilled(values.state)) {
             errors.state = 'Please select a state';
         }
-        if (!values.checkbox) {
+        if (!ValidationUtils.isRequiredFulfilled(values.checkbox)) {
             errors.checkbox = 'You must accept the Terms of Service to continue';
         }
         return errors;