javascript check undefined or null or empty code example

Example 1: javascript check if undefined or null

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

Example 2: javascript is not null

if(data !== null && data !== '') {
   // do something
}

Example 3: javascript check if not null

//Even if the value is 0, this will execute. 

if (myVar !== null) {...}

//If you don't want it to execute when it's 0, then set it as

if (myVar) {...}

//This will return false if var value is 0.

Example 4: javascript check if object is null or empty

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

Example 5: javascript check for null variables

var myVar=null;

if(myVar === null){
    //I am null;
}

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

Example 6: javascript syntax for check null or undefined or empty

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