CODEWITHSUNDEEP
arraystypescript
Zack Lucky
Zack Lucky

Reputation: 671

For of loop not being entered

I have an issue using .entries on an array to get index and value in a for of loop

ranks: any = {
    total: 100,    
    percentages: [
        {
            percentage: 33
        },
        {
            percentage: 33
        },
        {
            percentage: 34
        }
    ]
};

getMax(i: number){
    var max: number = 100;
    for (let [index,value] of this.ranks.percentages.entries()) {
        console.log(index, value.percentage);
        if(index !== i){
            max -= value.percentage;
        }
    }
    return max;
}

The console log is never logged in this case. I made a simple example that works so I must be missing something clearly obvious. 

array = [
  { name:12 },
  { name:23 },
  { name:34 }
]

for (let [index, value] of array.entries()) {
  console.log(index, value.name);
}

I'd normally try to console.log things to get at the issue but I'm not sure what to log or how I could use breakpoints since it skips over it.

Upvotes: 0

Views: 148

Answers (1)

user663031
user663031

Reputation:

TS compiles the for statement as

for (var _i = 0, _a = ranks.percentages.entries(); _i < _a.length; _i++) {

length of an iterator is undefined, so the for loop becomes a no-op.

In other words, it does not seem to know that entries() is yielding an iterable. Are you getting a compilation error about entries?

If you compile down to ES6, this works.

If you just want to get your code working, then just rewrite it as a basic for loop.

Upvotes: 2

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