Nested calculation with javascript & Angular (v1)

Question

I have an object like that:

vm.data = {
        a : {
            v : 25
        },
        b : {
            v : "",
            c : "f + a"
        },
        c : {
            v : "",
            c : "b + a"
        },
        d : {
            v : "",
            c : "c + e"
        },
        e : {
            v : "",
            c : "a + c"
        },
        f : {
            v : "",
            c : "b + c"
        }
    };

and I would like to have all these calculations done every time I change A. I cannot find a solution to solve this problem. Any idea?

PS: this is just an simple example of an object hundreds time bigger and complicated than this.

do you have stored in some place which change triggers which calculations ? or are they harcoded in code or something ? — Gonzalo.-
– Gonzalo.-, Commented Mar 7, 2017 at 20:30
@NinaScholz: can you give an example of a getter please? Gonzalo.- : I've got a service with this data and I've to calculate all these values every time I change one of them (in this case only A). — Ale
– Ale, Commented Mar 7, 2017 at 20:34

Nina Scholz · Accepted Answer · 2017-03-07 21:17:35Z

2

You could use a getter method for getting an actual value of the calculation of the properties.

var object = {
        a: 6,
        b: 42,
        get c() { 
            return this.a + this.b;
        }
    };
    
console.log(object.c);
object.a = 1000;
console.log(object.c);

var object = {
        a : 25,
        get b () { return this.a * 5; },
        get c () { return this.b + this.a; },
        get d () { return this.c + this.a; }
    }; 
    
console.log(object.d);
object.a = 1000;
console.log(object.d);

edited Mar 7, 2017 at 21:17

answered Mar 7, 2017 at 20:37

Nina Scholz

388k26 gold badges367 silver badges417 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Ale Over a year ago

it's a very good solution and it works well...I have just to find a way to change my original object in this way. The biggest problem is that I have to use parseInt to get numbers, otherwise it sees the values like strings. Thank you. PS: Any other suggestion is very welcome (I would like avoid to change the original object)!

Ale Over a year ago

PSS: it works in this way: vm.data = { a : 25, get b () { return this.a * 5 }, get c () { return parseInt(this.b) + parseInt(this.a) }, get d () { return parseInt(this.c) + parseInt(this.a) } }; but it doesn't work if, in c, a change this.b with this.d because d is calculated afterwards (I presume) ...and I have scenarios like that unfortunately.

Nina Scholz Over a year ago

you need the right order and prevent circular references.

Collectives™ on Stack Overflow

Nested calculation with javascript & Angular (v1)

1 Answer 1

3 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

3 Comments

Your Answer

Sign up or log in

Post as a guest

Related