source: imaps-frontend/node_modules/es-abstract/2017/GetSubstitution.js

'use strict';

var GetIntrinsic = require('get-intrinsic');

var $TypeError = require('es-errors/type');
var $parseInt = GetIntrinsic('%parseInt%');

var inspect = require('object-inspect');

var regexTester = require('safe-regex-test');
var callBound = require('call-bind/callBound');
var every = require('../helpers/every');

var isDigit = regexTester(/^[0-9]$/);

var $charAt = callBound('String.prototype.charAt');
var $strSlice = callBound('String.prototype.slice');

var IsArray = require('./IsArray');

var isInteger = require('../helpers/isInteger');
var isStringOrUndefined = require('../helpers/isStringOrUndefined');

// https://262.ecma-international.org/6.0/#sec-getsubstitution

// eslint-disable-next-line max-statements, max-lines-per-function
module.exports = function GetSubstitution(matched, str, position, captures, replacement) {
        if (typeof matched !== 'string') {
                throw new $TypeError('Assertion failed: `matched` must be a String');
        }
        var matchLength = matched.length;

        if (typeof str !== 'string') {
                throw new $TypeError('Assertion failed: `str` must be a String');
        }
        var stringLength = str.length;

        if (!isInteger(position) || position < 0 || position > stringLength) {
                throw new $TypeError('Assertion failed: `position` must be a nonnegative integer, and less than or equal to the length of `string`, got ' + inspect(position));
        }

        if (!IsArray(captures) || !every(captures, isStringOrUndefined)) {
                throw new $TypeError('Assertion failed: `captures` must be a List of Strings, got ' + inspect(captures));
        }

        if (typeof replacement !== 'string') {
                throw new $TypeError('Assertion failed: `replacement` must be a String');
        }

        var tailPos = position + matchLength;
        var m = captures.length;

        var result = '';
        for (var i = 0; i < replacement.length; i += 1) {
                // if this is a $, and it's not the end of the replacement
                var current = $charAt(replacement, i);
                var isLast = (i + 1) >= replacement.length;
                var nextIsLast = (i + 2) >= replacement.length;
                if (current === '$' && !isLast) {
                        var next = $charAt(replacement, i + 1);
                        if (next === '$') {
                                result += '$';
                                i += 1;
                        } else if (next === '&') {
                                result += matched;
                                i += 1;
                        } else if (next === '`') {
                                result += position === 0 ? '' : $strSlice(str, 0, position - 1);
                                i += 1;
                        } else if (next === "'") {
                                result += tailPos >= stringLength ? '' : $strSlice(str, tailPos);
                                i += 1;
                        } else {
                                var nextNext = nextIsLast ? null : $charAt(replacement, i + 2);
                                if (isDigit(next) && next !== '0' && (nextIsLast || !isDigit(nextNext))) {
                                        // $1 through $9, and not followed by a digit
                                        var n = $parseInt(next, 10);
                                        // if (n > m, impl-defined)
                                        result += n <= m && typeof captures[n - 1] === 'undefined' ? '' : captures[n - 1];
                                        i += 1;
                                } else if (isDigit(next) && (nextIsLast || isDigit(nextNext))) {
                                        // $00 through $99
                                        var nn = next + nextNext;
                                        var nnI = $parseInt(nn, 10) - 1;
                                        // if nn === '00' or nn > m, impl-defined
                                        result += nn <= m && typeof captures[nnI] === 'undefined' ? '' : captures[nnI];
                                        i += 2;
                                } else {
                                        result += '$';
                                }
                        }
                } else {
                        // the final $, or else not a $
                        result += $charAt(replacement, i);
                }
        }
        return result;
};