how to check whether the array of objects includes the specific object in node

Question

I have below code in node -

function ABC(a,b,c) {
    this.a = a;
    this.b = b;
    this.c = c;
    this.equals = function(other) {
     return other.a == this.a &&
      other.b == this.b &&
      other.c === this.c;
    };
}

var a1 =  new ABC("1", "1", 0.94924088690462316);
var a2 =  new ABC("1", "1", 0.94924088690462316);

console.log(a1 === a2);
var arr = [a1];
console.log(arr.includes(a2));

This code outputs is -

 false
 false

how can I check whether the array includes the specific object is true?

Are you expecting an output of true because their properties and values are all the same? — Snow
– Snow, Commented Jul 24, 2019 at 23:12

Snow · Accepted Answer · 2019-07-24 23:13:40Z

Since it look like you're trying to check whether the objects contain the same values, see that you've already defined an equals method - just use it:

function ABC(a,b,c) {
    this.a = a;
    this.b = b;
    this.c = c;
    this.equals = function(other) {
     return other.a == this.a &&
      other.b == this.b &&
      other.c === this.c;
    };
}

var a1 =  new ABC("1", "1", 0.94924088690462316);
var a2 =  new ABC("1", "1", 0.94924088690462316);

console.log(a1.equals(a2));

You can make the code more efficient by defining the method on the prototype:

function ABC(a, b, c) {
  this.a = a;
  this.b = b;
  this.c = c;
}

ABC.prototype.equals = function(other) {
  return other.a == this.a &&
    other.b == this.b &&
    other.c === this.c;
};

var a1 = new ABC("1", "1", 0.94924088690462316);
var a2 = new ABC("1", "1", 0.94924088690462316);

console.log(a1.equals(a2));

Also, keep in mind that 0.94924088690462316 holds too many significant figures for Javascript to handle - that number will be stored as 0.9492408869046232:

console.log(0.94924088690462316);

CrashCodes · Accepted Answer · 2019-07-24 23:22:55Z

2

Only slightly different from Snow's answer:

function ABC(a,b,c) {
    this.a = a;
    this.b = b;
    this.c = c;
    this.equals = function(other) {
     return other.a == this.a &&
      other.b == this.b &&
      other.c === this.c;
    };
}

var a1 =  new ABC("1", "1", 0.94924088690462316);
var a2 =  new ABC("1", "1", 0.94924088690462316);

console.log(a1.equals(a2));
var arr = [a1];
console.log(arr.some(abc => (a1.equals(abc))));

answered Jul 24, 2019 at 23:22

CrashCodes

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