Typescript 循环遍历一组值

Question

I have the following weird issue on my code using Typescript 2.6. I 'm trying to loop through a Set of string values but I get the following error and I don't understand why.

'Type 'Set' is not an array type or a string type. '

Here is what I have:

loopThroughSet(): void {

        let fruitSet = new Set()
        .add('APPLE')
        .add('ORANGE')
        .add('MANGO');

        for (let fruit of fruitSet) {
            console.log(fruit);
        }
}

Does anyone knows what's the problem? Thanks in advance

Answer 1

Set are not define in TS, you need to configure TS with es2017.object or convert Set values to array :

for (var item of Array.from(fruitSet.values())) {
  console.log(item);
}

Answer 2

You can use fruitSet.forEach( fruit => ... )

If you want to use for..of , try spread operator: for (const fruit of [...fruitsSet]) { ... }

Answer 3

In my case, I needed to iterate through a range of seven items without defining and using a variable that would be marked as unused by ESLint , and the spread syntax helped a lot.

[...Array(7)].map(() => {
    // some code
});

instead of

for (const _ of range(0, 7)) {
    // Some code
}