How to use regexpp - 10 common examples

if (!DOUBLE_SPACE.test(rawPattern)) {
                return;
            }

            const characterClassNodes = [];
            let regExpAST;

            try {
                regExpAST = regExpParser.parsePattern(pattern, 0, pattern.length, flags.includes("u"));
            } catch (e) {

                // Ignore regular expressions with syntax errors
                return;
            }

            regexpp.visitRegExpAST(regExpAST, {
                onCharacterClassEnter(ccNode) {
                    characterClassNodes.push(ccNode);
                }
            });

            const spacesPattern = /( {2,})(?: [+*{?]|[^+*{?]|$)/gu;
            let match;

            while ((match = spacesPattern.exec(pattern))) {
                const { 1: { length }, index } = match;

                // Report only consecutive spaces that are not in character classes.
                if (
                    characterClassNodes.every(({ start, end }) => index < start || end <= index)
                ) {
                    context.report({

/**
 * @fileoverview Validate strings passed to the RegExp constructor
 * @author Michael Ficarra
 */
"use strict";

//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------

const RegExpValidator = require("regexpp").RegExpValidator;
const validator = new RegExpValidator({ ecmaVersion: 2018 });
const validFlags = /[gimuys]/gu;
const undefined1 = void 0;

//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------

module.exports = {
    meta: {
        type: "problem",

        docs: {
            description: "disallow invalid regular expression strings in `RegExp` constructors",
            category: "Possible Errors",
            recommended: true,
            url: "https://eslint.org/docs/rules/no-invalid-regexp"

*/

"use strict";

//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------

const astUtils = require("./utils/ast-utils");
const regexpp = require("regexpp");

//------------------------------------------------------------------------------
// Helpers
//------------------------------------------------------------------------------

const regExpParser = new regexpp.RegExpParser();
const DOUBLE_SPACE = / {2}/u;

/**
 * Check if node is a string
 * @param {ASTNode} node node to evaluate
 * @returns {boolean} True if its a string
 * @private
 */
function isString(node) {
    return node && node.type === "Literal" && typeof node.value === "string";
}

//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------

// Requirements
//------------------------------------------------------------------------------

const {
    CALL,
    CONSTRUCT,
    ReferenceTracker,
    getStringIfConstant
} = require("eslint-utils");
const regexpp = require("regexpp");

//------------------------------------------------------------------------------
// Helpers
//------------------------------------------------------------------------------

const parser = new regexpp.RegExpParser();

//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------

module.exports = {
    meta: {
        type: "suggestion",

        docs: {
            description: "enforce using named capture group in regular expression",
            category: "Best Practices",
            recommended: false,
            url: "https://eslint.org/docs/rules/prefer-named-capture-group"
        },

function checkRegex(regex, node, uFlag) {
            let ast;

            try {
                ast = parser.parsePattern(regex, 0, regex.length, uFlag);
            } catch (_) {

                // ignore regex syntax errors
                return;
            }

            regexpp.visitRegExpAST(ast, {
                onCapturingGroupEnter(group) {
                    if (!group.name) {
                        const locNode = node.type === "Literal" ? node : node.arguments[0];

                        context.report({
                            node,
                            messageId: "required",
                            loc: {
                                start: {
                                    line: locNode.loc.start.line,
                                    column: locNode.loc.start.column + group.start + 1
                                },
                                end: {
                                    line: locNode.loc.start.line,
                                    column: locNode.loc.start.column + group.end + 1
                                }

let patternNode;

            try {
                patternNode = parser.parsePattern(
                    pattern,
                    0,
                    pattern.length,
                    flags.includes("u")
                );
            } catch (e) {

                // Ignore regular expressions with syntax errors
                return;
            }

            visitRegExpAST(patternNode, {
                onCharacterClassEnter(ccNode) {
                    for (const chars of iterateCharacterSequence(ccNode.elements)) {
                        for (const kind of kinds) {
                            has[kind] = has[kind] || hasCharacterSequence[kind](chars);
                        }
                    }
                }
            });

            for (const kind of kinds) {
                if (has[kind]) {
                    context.report({ node, messageId: kind });
                }
            }
        }

function parseRegExp(node) {
            const evaluated = eslint_utils_1.getStaticValue(node, globalScope);
            if (evaluated == null || !(evaluated.value instanceof RegExp)) {
                return null;
            }
            const { pattern, flags } = regexpp_1.parseRegExpLiteral(evaluated.value);
            if (pattern.alternatives.length !== 1 ||
                flags.ignoreCase ||
                flags.global) {
                return null;
            }
            // Check if it can determine a unique string.
            const chars = pattern.alternatives[0].elements;
            if (!chars.every(c => c.type === 'Character')) {
                return null;
            }
            // To string.
            return String.fromCodePoint(...chars.map(c => c.value));
        }
        return {

function parseRegExp(node: TSESTree.Node): string | null {
      const evaluated = getStaticValue(node, globalScope);
      if (evaluated == null || !(evaluated.value instanceof RegExp)) {
        return null;
      }

      const { pattern, flags } = parseRegExpLiteral(evaluated.value);
      if (
        pattern.alternatives.length !== 1 ||
        flags.ignoreCase ||
        flags.global
      ) {
        return null;
      }

      // Check if it can determine a unique string.
      const chars = pattern.alternatives[0].elements;
      if (!chars.every(c => c.type === 'Character')) {
        return null;
      }

      // To string.
      return String.fromCodePoint(

function forEachCapturingGroup(pattern, callback) {
		let number = 0;
		visitRegExpAST(pattern, {
			onCapturingGroupEnter(node) {
				callback({
					group: node,
					number: ++number
				});
			}
		});
	}

function verify(context, node, pattern, flags) {
    try {
        let found = false

        new RegExpValidator({
            onUnicodePropertyCharacterSet() {
                found = true
            },
        }).validatePattern(pattern, 0, pattern.length, flags.includes("u"))

        if (found) {
            context.report({ node, messageId: "forbidden" })
        }
    } catch (error) {
        //istanbul ignore else
        if (error.message.startsWith("Invalid regular expression:")) {
            return
        }
        //istanbul ignore next
        throw error
    }