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.
Es6 how to check if value is not null or undefined?
How to check if value id null or undefined. simple way is just check if has value! Like if(value) { // ... } will return true if value is not: null, undefined, NaN, empty string (""), 0, false It’s fulfill our requirements but also check additional conditions Like we want to check id is null or undefined but in response we got id = 0 In this condition it will fail because we just need to check null or undefined if(value !== undefined || value !== null){ // ... }
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