simple but advanced array-methods ES6/ES7 and so on

• Splice method: mute the original array
• Slice method: doesn't mute original array create new one

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• Reverse method: mute original array
• Concat method: doesn't mute original array
• Join method:

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• forEach: higher order function

const movements = [200, 450, -400, 3000, -650, -130, 70, 1300];
movements.forEach(function (movement) {
  if (movement > 0) {
    console.log(`You deposited ${movement}`);
  } else {
    console.log(`You withdrew ${Math.abs(movement)}`);
  }
});

movements.forEach(function (movement, index, array) {}

• first parameter the current element , second parameter always the current index of array, third one always the entire array

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• insertAdjacentHTML element.insertAdjacentHTML(position, text);

Map Method:

• map returns a new array containing the result of applying an operation on all original array elements.

Filter Method:

• filter returns a new array containing the array elements that passed a specified test condition.

Reduce Method:

• reduce boils ("reduces") all array elements down to one single value (e.g. adding all elements together)
• first parameter call accumulator . | like SNOWBALL| 2nd parameter current value .

Flat | flatMap

Sorting

return < 0, A, B, C (keep order)| return > 0, C, B, A (switch order)

• String and number together it's not work

// Ascending
movements.sort((a, b) => {
  if (a > b) return 1;
  if (a < b) return -1;
});
// or
movements.sort((a, b) => a - b);

// Descending
movements.sort((a, b) => {
  if (a > b) return -1;
  if (a < b) return 1;
});
// or
movements.sort((a, b) => b - a);

Empty arrays | fill method | Array.from method

const y = Array.from({ length: 7 }, () => 1); const z = Array.from({ length: 100 }, (_, i) => i++);

• Conversion console.log(+'23'); type coercion. | convert into number

Parsing in function

console.log(Number.parseInt('30px', 10)); console.log(Number.parseInt('e23', 10));

Checking if value is number

console.log(Number.isFinite(20)); console.log(Number.isFinite('20'));

Create Date

console.log(new Date(account1.movementsDates[0]));
console.log(new Date(0));
console.log(new Data(3 * 24 * 60 * 60 * 1000));
// working with date
const future = new Date(2037, 10, 19, 15, 23);
console.log(future);
console.log(future.getFullYear()); | never use .getYear
console.log(future.getMonth());
console.log(future.getDate());
console.log(future.getDay());
console.log(future.getHours());
console.log(future.getMinutes());
console.log(future.getSeconds());
console.log(future.toISOString()); | international

console.log(future.getTime());

console.log(Date.now());

future.setFullYear(2040);
console.log(future);

Internationalizing Dates(intl) labelDate.textContent = new Intl.DateTimeFormat('en-US').format(now);

Intl

setTimeout()