Iterations

For Loop

for(let x : number = 0; x > 10; x++) console.log(x);
// output: 0 through 9 (stops before 10)

For loop with array

let numarrs:number[] = [10, 20, 30, 40, 50, 60, 70, 80, 90, 100];
for(let y:number=0; y < numarrs.length; y++){
    console.log(numarrs[y]);
    // 10, 20, 30, ..., 100.
}

For loop with mixed array (traditional loop)

let mixarrs : (string|number)[] = ["red", "green", 100, 200, 300, "blue"];
for(let p:number=0; p < mixarrs.length; p++){
    console.log(mixarrs[p]);
    // output : "red", "green", 100, 200, 300, "blue"
}

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For of loop

for(let mixarr of mixarrs) console.log(mixarr);
// output : "red", "green", 100, 200, 300, "blue" 

for(let mix of mixarrs.entries()) console.log(mix[0], mix[1]);
// The entries() method returns an Iterator object 
// with the key/value pairs from an array: mix = ["0", "red"] in 1st loop
// output :
// 0 "red"
// 1 "green"
// 2 100
// 3 200
// 4 300
// 5 "blue"

for(let [idx, val] of mixarrs.entries()) console.log(idx, val);
// output :
// 0 red
// 1 green
// 2 100
// 3 200
// 4 300
// 5 blue

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For in loop

for(let key in mixarrs) console.log(mixarrs[key]);
// key : 0 to 5 
// output : "red", "green", 100, 200, 300, "blue"

for(let key in mixarrs){
    console.log(`${+key+1} . ${mixarrs[key]}`);
}
// key is string so add + to key (+key) to convert string to number
// output :
// 1 . red
// 2 . green
// 3 . 100
// 4 . 200
// 5 . 300
// 6 . blue