TypeScript null operator

You can use the qualities of the abstract equality operator to do this: if (variable == null){ // your code here. } Because null == undefined is true, the above code will catch both null and undefined .

Use Object. keys(obj). length to check if it is empty.

JavaScript uses the null value to represent a missing object. Use the strict equality operator ( === ) to check if a value is null . The typeof null returns ‘object’ , which is historical bug in JavaScript that may never be fixed.

Undefined is the default value for uninitialized variables But TypeScript never assigns null to any variable . We have to assign Null to variable to make it null. Note that in the example above foo is of type any, which means that no type checking.