source: frontend/node_modules/webpack/lib/util/LocConverter.js

/*
        MIT License http://www.opensource.org/licenses/mit-license.php
        Author Alexander Akait @alexander-akait
*/

"use strict";

class LocConverter {
        /**
         * Creates an instance of LocConverter.
         * @param {string} input input
         */
        constructor(input) {
                this._input = input;
                this.line = 1;
                this.column = 0;
                this.pos = 0;
        }

        /**
         * Returns location converter.
         * @param {number} pos position
         * @returns {LocConverter} location converter
         */
        get(pos) {
                if (this.pos !== pos) {
                        if (this.pos < pos) {
                                const str = this._input.slice(this.pos, pos);
                                let i = str.lastIndexOf("\n");
                                if (i === -1) {
                                        this.column += str.length;
                                } else {
                                        this.column = str.length - i - 1;
                                        this.line++;
                                        while (i > 0 && (i = str.lastIndexOf("\n", i - 1)) !== -1) {
                                                this.line++;
                                        }
                                }
                        } else {
                                let i = this._input.lastIndexOf("\n", this.pos);
                                while (i >= pos) {
                                        this.line--;
                                        i = i > 0 ? this._input.lastIndexOf("\n", i - 1) : -1;
                                }
                                this.column = i === -1 ? pos : pos - i - 1;
                        }
                        this.pos = pos;
                }
                return this;
        }
}

module.exports = LocConverter;