有如下多层嵌套的对象:

var obj = {  l1: {    l2: {      l3: "Hello World"    }  }}

 

方法1:

var r = (((obj || {}).l1 || {}).l2 || {}).l3;

var r = obj.l1 && obj.l1.l2 && obj.l1.l2.l3

 

方法2:

let delve = (obj, key) => (key.split('.').map(p => (obj = obj && obj[p])), obj);console.log(delve(obj, 'l1.l2.l3')); // Hello World

 

方法3:

function checkNested(obj, key, ...rest) {  if (obj === undefined || obj === null) return false;  if (rest.length == 0 && obj.hasOwnProperty(key)) return true;  return checkNested(obj[key], ...rest);}console.log(checkNested(obj, 'l1', 'l2', 'l3')); // true

 

方法4:

function validChain(obj, ...keys) {  return keys.reduce((obj, key) => (obj || {})[key], obj) !== undefined}console.log(validChain(obj, 'l1', 'l2', 'l3')); // true

 

方法5:

function objHasKeys(obj, keys) {  var next = keys.shift();  return obj[next] && (! keys.length || objHasKeys(obj[next], keys));}

如果有更好的方式,欢迎补充????。