better-decode-uri-component/index.js

Safe and maximum possible decodeURIComponent

((g,f)=>{typeof module=='object'?module.exports=f():typeof define=='function'&&define.amd?define([],f):g.betterDecodeURIComponent=f();typeof exports=='object'&&(exports.default=exports.betterDecodeURIComponent=f());})(typeof self!='undefined'?self:this,()=>{
    function betterDecodeURIComponent(str, { maxSequenceSize = 4, removeMalform = true } = {}) {
        if (typeof str !== 'string') throw new TypeError('Expected string but got ' + typeof str);

        try { return decodeURIComponent(str); } catch(e) {}

        return str.replace(/(?:%[0-9A-Fa-f]{2})+/g, match => {
            let res = '';

            let pos = 0;
            while (pos < match.length) {
                let decoded = false;

                for (let len = Math.min(match.length - pos, maxSequenceSize * 3); len >= 3; len -= 3) {
                    const sub = match.substring(pos, pos + len);

                    try {
                        res += decodeURIComponent(sub);
                        pos += len;
                        decoded = true;
                        break;
                    } catch(e) {}
                }

                if (!decoded) {
                    if (!removeMalform) res += match.substring(pos, pos + 3);
                    pos += 3;
                }
            }

            return res;
        });
    }

    return betterDecodeURIComponent;
});