便利に使えそうなイコール関数

2015-07-19-a.js

function generic_equal(a, b) {
    // 同じ own プロパティの集合を持っている
    function object_equal(a, b) {
        if (typeof(a) != 'object' || typeof(b) != 'object')
            throw new Error('object');

        var aKeys = Object.keys(a);
        var bKeys = Object.keys(b);

        if (aKeys.length != bKeys.length)
            return false;

        aKeys.sort();

        var i;
        for (i = 0; i < aKeys.length; i++) {
            var key = aKeys[i];
            if (!b.hasOwnProperty(key))
                return false;
            if (!generic_equal(a[key], b[key]))
                return false;
        }
        return true;
    }

    // オブジェクト参照同一、プリミティブ同値。
    if (a === b)
        return true;

    if (typeof(a) != typeof(b))
        return false;

    if (typeof(a) == 'object')
        return object_equal(a, b);
    else
        return false;
}

console.assert( generic_equal( 1, 1 ) );
console.assert( generic_equal( [1], [1] ) );
console.assert( generic_equal( [1,2], [1,2] ) );
console.assert( generic_equal( [[1]], [[1]] ) );
console.assert( generic_equal( [[[]]], [[[]]] ) );
console.assert( generic_equal( {a:1}, {a:1}) );
console.assert( generic_equal( [{a:1}], [{a:1}] ) );
console.assert( generic_equal( {a:1,b:2}, {b:2,a:1} ) );

console.assert( !generic_equal(1, 2) );
console.assert( !generic_equal(1, "1") );
console.assert( !generic_equal(0, null) );
console.assert( !generic_equal([1], [2]) );
console.assert( !generic_equal([], [[]]) );
console.assert( !generic_equal([{a:[1]}], [{a:[2]}]) );