Getting JavaScript object key list vol. 2

You can use mix of Object.keys and Array#flatMap.

let obj = [
   { key1: 'value1' },
   { key2: 'value2' },
   { key3: 'value3' },
   { key4: 'value4' },
];

let keys = obj.flatMap(Object.keys);

console.log(keys);


you can get keys for each object in obj and then use concat() to add it to your result array.

    var obj = [
       {
           key1: 'value1'
       },
       {
           key2: 'value2'
       },
       {   
           key3: 'value3'
       },
       {   
           key4: 'value4'
       }
    ]
var keyList = [];
obj.forEach(function(o){
    keyList = keyList.concat(Object.keys(o));
});
console.log(keyList);


You can achieve it using Array#reduce method.

var obj = [{
  key1: 'value1'
}, {
  key2: 'value2'
}, {
  key3: 'value3'
}, {
  key4: 'value4'
}];

var res = obj
  // iterate over the array
  .reduce(function(arr, o) {
    // get keys and push into the array
    [].push.apply(arr, Object.keys(o));
    // return the araray reference
    return arr;
    // set initial value as an empty array
  }, []);

console.log(res);

// ES6 alternative
var res1 = obj.reduce((arr, o) => (arr.push(...Object.keys(o)), arr), []);

console.log(res1);

Tags:

Javascript

Arrays

Object

Recent Posts