How to check variable is an array es6
const arr = [1,5,7];
const result = Array.isArray(arr);
Or
in Lodash:
const result = _.isArray(arr);
note: typeof []; // returns 'object'
and arr.length check will fail if variable is a string.
Check the existence of a key in JavaScript Object
How to check the existence of a key in JavaScript Object const myObj = { a: 1, b: 2}; We need to check whether I’d exist in object or not! const result = myObj.hasOwnProperty('id'); // false Or const result = 'id' in myObj; // false Or const result = myObj.id !== undefined; // false
Comments