@handy-common-utils/misc-utils/dist/substitute.js

Miscellaneous utilities

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.substituteAll = void 0;
/**
 * Substitute all occurrences of a pattern in a string.
 * @param input The input string on which the substitutions will be performed.
 * @param searchPattern The regular expression pattern used to search for segments that should be substituted.
 *        It must have the `g` flag set.
 *        If the beginning part of the `input` should be skipped, set the `lastIndex` of the `searchPattern` before calling this function.
 *        After all the substitution are done, the `lastIndex` of the `searchPattern` will be reset to zero.
 *        See {@link https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/lastIndex}
 * @param substitute TThe function that builds the substitution string.
 *        It is called with the matched substring and the result of `RegExp.exec()`.
 *        See {@link https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/exec#examples}.
 *        The function can return null to indicate that no further substitution is desired.
 *        In such case, the `lastIndex` of the `searchPattern` will not be reset to zero.
 * @returns The resulting string after performing all substitutions.
 */
function substituteAll(input, searchPattern, substitute) {
    if (input == null) {
        return input;
    }
    if (!searchPattern.global) {
        throw new Error('searchPattern must have the g flag');
    }
    const segments = [];
    let result;
    let previousLastIndex = 0;
    while ((result = searchPattern.exec(input)) !== null) {
        const substitution = substitute(result[0], result);
        if (substitution == null) { // append the remaining and exit
            segments.push(input.slice(previousLastIndex));
            previousLastIndex = input.length;
            break;
        }
        segments.push(input.slice(previousLastIndex, searchPattern.lastIndex - result[0].length), substitution);
        previousLastIndex = searchPattern.lastIndex;
    }
    if (segments.length === 0) { // no matching at all
        return input;
    }
    if (previousLastIndex < input.length) { // remaining part
        segments.push(input.slice(previousLastIndex));
    }
    return segments.join('');
}
exports.substituteAll = substituteAll;