CODEWITHSUNDEEP
javascriptarraysvariablesobjectconstructor
Cathedral Zealot
Cathedral Zealot

Reputation: 131

Print name of constructor variable

Say, I have 2 constructors assigned to 2 variables:

var example1 = function(argument1){
    this.argument1 = argument1;
}

var example2 = function(argument2){
    this.argument2 = argument2;
}

And an array of objects containing objects from both of these constructors:

var array1 = new Array();
array1[0] = new example1(example);
array1[1] = new example2(example);

My question is, when I choose an item from the array, how can I print the name of the constructor variable it came from?

To make this clear and succint, here's an example:

console.log(array1[0].argument1)

Will print example. But I don't want that. I want it to print the name of the constructor variable it came from.

console.log(array1[0].constructor.toString());

Prints the content of the variable, but it is unsatisfactory.

Upvotes: 1

Views: 1849

Answers (3)

Ceres
Ceres

Reputation: 3658

Try instance of, 

var example1 = function(argument1){
    this.argument1 = argument1;
}

var example2 = function(argument2){
    this.argument2 = argument2;
}

console.log(getName(array1[0]));

function getName(value) {

    if (value instanceof example1) return 'example1';
    if (value instanceof example2) return 'example2';

    return '';

}

Upvotes: -1

dandavis
dandavis

Reputation: 16726

in most browsers, functions have a name, but you don't use it. so, we have to resort to hacks to find your constructor in the cloud, which won't work in IE7, maybe 8:

console.log(Object.keys(self).filter(function(a){
     return self[a]===array1[0].constructor;
})[0]);

if you didn't have the code running in the global scope, this trick won't work! again, this is a hack and you should find a better way of doing things, like naming your functions, even if they are expressions.

Upvotes: 0

pvnarula
pvnarula

Reputation: 2831

You need to provide a name to a function:-

var example1 = function example1(argument1){
    this.argument1 = argument1;
}
 var array1 = new Array();
array1[0] = new example1({});

console.log(array1[0].constructor.name)

Upvotes: 3

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