js for loop with index code example

Example 1: for of get index

for (const v of ['a', 'b', 'c']) {
  console.log(v)
}

// get index
for (const [i, v] of ['a', 'b', 'c'].entries()) {
  console.log(i, v)
}

Example 2: javascript enumerate with index

const iterable = [...];
for (const [index, elem] in iterable.entries()) {
  f(index, elem);
}

// or
iterable.forEach((elem, index) => {
  f(index, elem);
});

Example 3: for of loop syntax javascript

for (let step = 0; step < 5; step++) {
  // Runs 5 times, with values of step 0 through 4.
  console.log('Walking east one step');
}

Example 4: js get index from foreach

var myArray = [123, 15, 187, 32];

myArray.forEach(function (value, i) {
    console.log('%d: %s', i, value);
});

// Outputs:
// 0: 123
// 1: 15
// 2: 187
// 3: 32

Example 5: javascript for loop return index

const targetindex = myarray.findIndex(item => item.name === 'xyz');