fast-replaceall/dist/index.js

Supports global replacement, case-insensitive mode, start index control, and functional replacement compatible with native `String.replace`.

"use strict";
function fitIndex(fromIndex, length) {
  return fromIndex ? fromIndex < 0 ? Math.max(0, length + fromIndex) : Math.min(fromIndex, length - 1) : 0;
}
function processBlankSegment(str, replacement, isFn, index) {
  return isFn ? replacement("", index, str) : replacement;
}
function handleZeroLengthEdgeCase(str, len, replacement, isFn) {
  let result = `${processBlankSegment(str, replacement, isFn, 0)}`;
  for (let i = 0; i < len; i++) {
    result += str[i] + processBlankSegment(str, replacement, isFn, i + 1);
  }
  return result;
}
function replaceAll(str, substr, replacement, options) {
  if (typeof str !== "string") {
    return str;
  }
  if (typeof substr !== "string") {
    return str;
  }
  const isFn = typeof replacement === "function";
  const substrLen = substr.length;
  const totalLen = str.length;
  if (substrLen === 0) {
    return handleZeroLengthEdgeCase(str, totalLen, replacement, isFn);
  }
  const { fromIndex, caseInsensitive } = options || {};
  let currentIndex = fitIndex(fromIndex, totalLen);
  let searchStr = substr;
  let sourceStr = str;
  if (caseInsensitive) {
    searchStr = substr.toLowerCase();
    sourceStr = str.toLowerCase();
  }
  let result = "";
  let lastIndex = 0;
  while (currentIndex <= totalLen - substrLen) {
    const matchIndex = sourceStr.indexOf(searchStr, currentIndex);
    if (matchIndex === -1) {
      break;
    }
    result += str.slice(lastIndex, matchIndex);
    if (isFn) {
      result += replacement(
        str.slice(matchIndex, matchIndex + substrLen),
        matchIndex,
        str
      );
    } else {
      result += replacement;
    }
    lastIndex = matchIndex + substrLen;
    currentIndex = lastIndex;
  }
  return lastIndex === 0 ? str : result + str.slice(lastIndex);
}
module.exports = replaceAll;