string.js

function trim(s) {
    return typeof s.trim != 'undefined' ? s.trim() : s.replace(/^\s+|\s+$/g, '');
}

function ltrim(s) {
    return typeof s.ltrim != 'undefined' ? s.ltrim() : s.replace(/^\s+/, '');
}

function rtrim(s) {
    return typeof s.rtrim != 'undefined' ? s.rtrim() : s.replace(/\s+$/, '');
}

function wrap(s, w, br) {
    w = w || 80;
    if (s.length <= w) {
        return s;
    }
    br = br || '\n';
    // /(.{1,80})[\t\r\x20]+|(.{1,80})/g
    var re = new RegExp('(.{1,' + w + '})[\\t\\r\\x20]+|(.{1,' + w + '})', 'g');
    s = s.split('\n');
    for (var i = 0; i < s.length; ++i) {
        if (s[i].length > w) {
            s[i] = s[i].match(re).map(function (v) {
                return rtrim(v);
            }).join(br);
        }
    }
    return s.join('\n');
}

function startsWith(haystack, needle) {
    return needle == haystack.substr(0, needle.length);
}

function endsWith(haystack, needle) {
    return needle == haystack.substr(-needle.length);
}

function containsStr(haystack, needle) {
    return haystack.indexOf(needle) >= 0;
}

function randStr(len, chars) {
    var ret = '';
    chars = chars || '1234567890qwertyuiopasdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVBNM';
    while (ret.length < len) {
        ret += chars.charAt(Math.random() * chars.length);
    }
    return ret;
}

function ucfirst(s) {
    return s.charAt(0).toUpperCase() + s.substr(1);
}

function capitalize(s) {
    return s.replace(/\b[a-z]/g, function (c) {
        return c.toUpperCase();
    });
}

function reverseStr(s) {
    return s.split('').reverse().join('');
}

function repeatStr(s, n) {
    return Array(++n).join(s);
}

function lpad(s, l, c) {
    if (s.length >= l) return s;
    c = c || ' ';
    while (s.length < l) {
        s = c + s;
    }
    return s.length > l ? s.substr(0, l) : s;
}

function rpad(s, l, c) {
    if (s.length >= l) return s;
    c = c || ' ';
    while (s.length < l) {
        s += c;
    }
    return s.length > l ? s.substr(0, l) : s;
}

function center(s, l, c) {
    if (s.length >= l) return s;
    c = c || ' ';
    l -= s.length;
    l /= 2;
    var repeater = repeatStr(c, Math.ceil(l / c.length));
    return repeater.substr(0, Math.floor(l)) + s + repeater.substr(0, Math.ceil(l))
}

function escapeRe(s) {
    return s.replace(/([-.\\+*?[^\]$(){}=!<>|:])/g, '\\$1');
}

function addSlashes(s) {
    return s.replace(/([\\'"])/g, '\\$1');
}

function stripSlashes(s) {
    return s.replace(/\\([\\'"])/g, '$1');
}

function encodeHtml(s) {
    return s.replace(/[<>&"']/g, function (c) {
        return  {
            '<': '&lt;',
            '>': '&gt;',
            '&': '&amp;',
            '"': '&quot;',
            "'": '&#39;'
        }[c];
    });
}

function decodeHtml(s) {
    var el = document.createElement('div');
    s = s.replace('<', '&lt;');
    s = s.replace('>', '&gt;');
    el.innerHTML = s;
    return el.textContent;
}

function encodeEntities(s) {
    var r = '';
    for (var i = 0; i < s.length; ++i) {
        r += '&#' + s.charCodeAt(i) + ';';
    }
    return r;
}

function stripTags(s) {
    return s.replace(/<[\s\S]+?>/g, '');
}

function template(s, o) {
    return s.replace(/\{(.*?)\}/g, function (m, v) {
        var ks = v.split('.'), r = o;
        for (var i = 0; i < ks.length; ++i) {
            r = r[ks[i]];
        }
        return r;
    });
}

function format(s) {
    var arg = toArray(arguments).slice(1);
    return s.replace(/\{(\d+)\}/g, function (match, index) {
        if (index >= arg.length) {
            throw new Error('Index out of range');
        }
        return arg[index];
    });
}