js check for undefined and null code example

Example 1: javascript check if undefined or null

if( typeof myVar === 'undefined' || myVar === null ){
    // myVar is undefined or null
}

Example 2: null undefined javascript

Undefined  used for unintentionally missing values.

Null       used for intentionally missing values.

Example 3: javascript syntax for check null or undefined or empty

if (typeof value !== 'undefined' && value) {
    //deal with value'
};