Javascript dynamically invoke object method from string

Question

Can I dynamically call an object method having the method name as a string? I would imagine it like this:

var FooClass = function() {
 this.smile = function() {};
}
var method = "smile";
var foo = new FooClass();
// I want to run smile on the foo instance.
foo.{mysterious code}(); // being executed as foo.smile();

Answer 1

if the name of the property is stored in a variable, use []

foo[method]();

• stackdave: it's not working for me using a variable inside a function:const genericResolver = ( table, action , values ) => { return Auth.isAuthenticated() .then(() => { return eval(table).findAll()
• schlingel: If you want to execute a method from another method inside a class, use this['methodName']().
• Anand Rockzz: Getting this ugly error Element implicitly has an 'any' type because expression of type 'string' can't be used to index type 'FooClass' anyone else ?

Answer 2

Properties of objects can be accessed through the array notation:

var method = "smile";
foo[method](); // will execute the method "smile"

Answer 3

When we call a function inside an object, we need provide the name of the function as a String.

var obj = {talk: function(){ console.log('Hi') }};
obj['talk'](); //prints "Hi"
obj[talk]()// Does not work

• Phil Cooper: It's always helpful to provide some commentary with your code so it can be understood out of context.
• s.n: Added some comment. Thanks!
• padina: I think: Your last code-line will work, if you declare let talk = 'talk'; obj[talk]() // prints "Hi"

Answer 4

method can be call with eval eval("foo." + method + "()"); might not be very good way.

• Rorrim: Useful in my case where foo is { fields: [{ id: 1 }] } and method is fields[0]?.id, but I had to remove () from your proposed answer

Answer 5

I would like to leave an example here for this. For example; i want to call a dynamically check method while submitting the form.

<form data-before-submit="MyObject.myMethod">
 <button type="submit">Submit</button>
</form>

$('form').on('submit', function(e){
 
 var beforeSubmit = $(this).attr('data-before-submit');
 if( beforeSubmit ){
 params = beforeSubmit.split(".");
 objectName = params[0];
 methodName = params[1];
 result = window[objectName][methodName]($(this));
 if( result !== true ){
 e.preventDefault();
 }
 }
});

var MyObject = {
 myMethod: function(form){
 console.log('worked');
 return true;
 }
};