拍平

数组拍平

    var arr = [1, [[[2, 3], 4, 5], 6]];
    function f(arr) {
        if (Object.prototype.toString.call(arr) !== "[object Array]")
            return;
        var newArr = [];
        var j = 0;
        function fn(arr) {
            for (var i = 0; i < arr.length; i++) {
                if (arr[i].length && (j <= 3)) {
                    j += 1;
                    fn(arr[i]);
                } else {
                    newArr.push(arr[i]);
                }
            }
        }
        fn(arr);
        return newArr;
    }
    arr = f(arr);
    console.log(arr);

对象拍平

• 严格拍扁

    var arr = [{
        a: "0",
        s: [
            {a: "1", s: [{a: "2"}, {a: "3"}, {a: "4"}]}, 
            {a: "6", s: [{a: "7"}, {a: "8"}, {a: "9"}]},
            {e: "10"}
        ]
    }];

  
    function f(arr, str) {
        arr.map(function (e, i) {
            if (str in e) {
                this.loop(e[str], str);
            }
        });
        return arr;
    }
    function loop(arr, str) {
        if (arr instanceof Array) {
            arr.map(function (er, ir) {
                if (str in er) {
                    b(arr, er[str], ir);
                    delete er[str];
                    this.loop(arr, str);
                }
            });
        }
    }
    function b(array, childArr, index) {
        var n = index + 1;
        childArr.map(function (e) {
            array.splice(n, 0, e);
            n++;
        });
        return array;
    }
    console.log(f(arr, "s"));

• 只支持每层一项

   var arr = [
        {
            a: "0",
            s: [{
                a: "1",
                s: [{b: "2", s: [{c: "3"}]}]
            }]
        }
    ];

var arr = [{a: "0", s: [{a: "1", s: [{b: "2", s: [{c: "3"}]}]}]}];
    function flatten(arr, str) {
        var array = [];
        arr.map(function (e, i) {
            getFlattenedObj(array, str, e);
        });
        return array;
    }
    function getFlattenedObj(newArr, str, obj) {
        if (str in obj) {
            if (obj[str] instanceof Array) {
                obj[str].map(function (e) {
                    getFlattenedObj(newArr, str, e);
                });
                delete obj[str];
            }
        }
        newArr.unshift(obj);
    }
    console.log(flatten(arr, "s"));