放入一个函数，简短而快速（无递归）。

var createNestedObject = function( base, names ) {
    for( var i = 0; i < names.length; i++ ) {
        base = base[ names[i] ] = base[ names[i] ] || {};
    }
};

// Usage:
createNestedObject( window, ["shapes", "triangle", "points"] );
// Now window.shapes.triangle.points is an empty object, ready to be used.

它跳过层次结构中已经存在的部分。如果您不确定层次结构是否已创建，则很有用。

或者：

一个更好的版本，您可以直接将值分配给层次结构中的最后一个对象，并且您可以链接函数调用，因为它返回最后一个对象。

// Function: createNestedObject( base, names[, value] )
//   base: the object on which to create the hierarchy
//   names: an array of strings contaning the names of the objects
//   value (optional): if given, will be the last object in the hierarchy
// Returns: the last object in the hierarchy
var createNestedObject = function( base, names, value ) {
    // If a value is given, remove the last name and keep it for later:
    var lastName = arguments.length === 3 ? names.pop() : false;

    // Walk the hierarchy, creating new objects where needed.
    // If the lastName was removed, then the last object is not set yet:
    for( var i = 0; i < names.length; i++ ) {
        base = base[ names[i] ] = base[ names[i] ] || {};
    }

    // If a value was given, set it to the last name:
    if( lastName ) base = base[ lastName ] = value;

    // Return the last object in the hierarchy:
    return base;
};

// Usages:

createNestedObject( window, ["shapes", "circle"] );
// Now window.shapes.circle is an empty object, ready to be used.

var obj = {}; // Works with any object other that window too
createNestedObject( obj, ["shapes", "rectangle", "width"], 300 );
// Now we have: obj.shapes.rectangle.width === 300

createNestedObject( obj, "shapes.rectangle.height".split('.'), 400 );
// Now we have: obj.shapes.rectangle.height === 400

注意：如果您的层次结构需要从标准对象（即 not {}）以外的值构建，另请参阅下面的 TimDog 的回答。

编辑：使用常规循环而不是for...in循环。在库修改 Array 原型的情况下更安全。

function assign(obj, keyPath, value) {
   lastKeyIndex = keyPath.length-1;
   for (var i = 0; i < lastKeyIndex; ++ i) {
     key = keyPath[i];
     if (!(key in obj)){
       obj[key] = {}
     }
     obj = obj[key];
   }
   obj[keyPath[lastKeyIndex]] = value;
}

用法：

var settings = {};
assign(settings, ['Modules', 'Video', 'Plugin'], 'JWPlayer');

我的 ES2015 解决方案。保留现有值。

const set = (obj, path, val) => { 
    const keys = path.split('.');
    const lastKey = keys.pop();
    const lastObj = keys.reduce((obj, key) => 
        obj[key] = obj[key] || {}, 
        obj); 
    lastObj[lastKey] = val;
};

例子：

const obj = {'a': {'prop': {'that': 'exists'}}};
set(obj, 'a.very.deep.prop', 'value');
console.log(JSON.stringify(obj));
// {"a":{"prop":{"that":"exists"},"very":{"deep":{"prop":"value"}}}}

使用 ES6 缩短了。将您的路径设置为数组。首先，您必须反转数组，以开始填充对象。

let obj = ['a','b','c'] // {a:{b:{c:{}}}
obj.reverse();

const nestedObject = obj.reduce((prev, current) => (
    {[current]:{...prev}}
), {});

另一个递归解决方案：

var nest = function(obj, keys, v) {
    if (keys.length === 1) {
      obj[keys[0]] = v;
    } else {
      var key = keys.shift();
      obj[key] = nest(typeof obj[key] === 'undefined' ? {} : obj[key], keys, v);
    }

    return obj;
};

用法示例：

var dog = {bark: {sound: 'bark!'}};
nest(dog, ['bark', 'loudness'], 66);
nest(dog, ['woff', 'sound'], 'woff!');
console.log(dog); // {bark: {loudness: 66, sound: "bark!"}, woff: {sound: "woff!"}}