unexpected/lib/utils.js

Extensible BDD assertion toolkit

/* jshint proto:true */
var canSetPrototype = Object.setPrototypeOf || ({ __proto__: [] } instanceof Array);

var setPrototypeOf = Object.setPrototypeOf || function setPrototypeOf(obj, proto) {
    obj.__proto__ = proto;
    return obj;
};
/* jshint proto:false */

var utils = module.exports = {
    objectIs: Object.is || function (a, b) {
        // Polyfill from https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/is
        if (a === 0 && b === 0) {
            return 1 / a === 1 / b;
        }
        if (a !== a) {
            return b !== b;
        }
        return a === b;
    },

    isArray: function (ar) {
        return Object.prototype.toString.call(ar) === '[object Array]';
    },

    isRegExp: function (re) {
        return (Object.prototype.toString.call(re) === '[object RegExp]');
    },

    isError: function (err) {
        return typeof err === 'object' && (Object.prototype.toString.call(err) === '[object Error]' || err instanceof Error);
    },

    extend: function (target) {
        for (var i = 1; i < arguments.length; i += 1) {
            var source = arguments[i];
            if (source) {
                Object.keys(source).forEach(function (key) {
                    target[key] = source[key];
                });
            }
        }
        return target;
    },

    findFirst: function (arr, predicate, thisObj) {
        var scope = thisObj || null;
        for (var i = 0 ; i < arr.length ; i += 1) {
            if (predicate.call(scope, arr[i], i, arr)) {
                return arr[i];
            }
        }
        return null;
    },

    leftPad: function (str, width, ch) {
        ch = ch || ' ';
        while (str.length < width) {
            str = ch + str;
        }
        return str;
    },

    escapeRegExpMetaChars: function (str) {
        return str.replace(/[[\]{}()*+?.\\^$|]/g, '\\$&');
    },

    escapeChar: function (ch) {
        if (ch === '\t') {
            return '\\t';
        } else if (ch === '\r') {
            return '\\r';
        } else {
            var charCode = ch.charCodeAt(0);
            var hexChars = charCode.toString(16).toUpperCase();
            if (charCode < 256) {
                return '\\x' + utils.leftPad(hexChars, 2, '0');
            } else {
                return '\\u' + utils.leftPad(hexChars, 4, '0');
            }
        }
    },

    getFunctionName: function (f) {
        if (typeof f.name === 'string') {
            return f.name;
        }
        var matchFunctionName = Function.prototype.toString.call(f).match(/function ([^\(]+)/);
        if (matchFunctionName) {
            return matchFunctionName[1];
        }

        if (f === Object) {
            return 'Object';
        }
        if (f === Function) {
            return 'Function';
        }
    },

    wrapConstructorNameAroundOutput: function (output, obj) {
        var constructor = obj.constructor;
        var constructorName = constructor && constructor !== Object && utils.getFunctionName(constructor);
        if (constructorName && constructorName !== 'Object') {
            return output.clone().text(constructorName + '(').append(output).text(')');
        } else {
            return output;
        }
    },

    setPrototypeOfOrExtend: canSetPrototype ? setPrototypeOf : function extend(target, source) {
        for (var prop in source) {
            if (source.hasOwnProperty(prop)) {
                target[prop] = source[prop];
            }
        }
        return target;
    },

    uniqueStringsAndSymbols: function () { // [filterFn], item1, item2...
        var filterFn;
        if (typeof arguments[0] === 'function') {
            filterFn = arguments[0];
        }
        var index = {};
        var uniqueStringsAndSymbols = [];

        function visit(item) {
            if (Array.isArray(item)) {
                item.forEach(visit);
            } else if (!index[item] && (!filterFn || filterFn(item))) {
                index[item] = true;
                uniqueStringsAndSymbols.push(item);
            }
        }

        for (var i = filterFn ? 1 : 0 ; i < arguments.length ; i += 1) {
            visit(arguments[i]);
        }
        return uniqueStringsAndSymbols;
    },

    uniqueNonNumericalStringsAndSymbols: function () { // ...
        return utils.uniqueStringsAndSymbols(function (stringOrSymbol) {
            var isSymbol;
            /*jshint ignore:start*/
            isSymbol = typeof stringOrSymbol === 'symbol';
            /*jshint ignore:end*/
            return isSymbol || !utils.numericalRegExp.test(stringOrSymbol);
        }, Array.prototype.slice.call(arguments));
    },

    numericalRegExp: /^(?:0|[1-9][0-9]*)$/
};