What is the difference between Map and foreach in Array?
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## Understanding the Difference Between `map` and `forEach` in JavaScript Arrays
In a technical interview, it's important to mention that both methods iterate over an array, but the difference is that the `map` method is `immutable` and will create a new array based on the original, while the `forEach` method simply iterates over it without returning any result.
### Example Breakdown
To illustrate the difference, let's consider an example where we multiply each element of the array and then return the result. In the case of `map`, you will get a new array, while with `forEach`, you will need to use a closure to store the result.
#### Using `map`
```javascript
const temperatures = [32, 45, 50, 60];
const increasedTemperatures = temperatures.map((temp) => temp + 10);
console.log(increasedTemperatures); // [42, 55, 60, 70]
console.log(temperatures); // [32, 45, 50, 60] - original remains unchangedUsing forEach
javascript
const tempArray = [32, 45, 50, 60];
const adjustedTemps = [];
tempArray.forEach((temp) => {
adjustedTemps.push(temp + 10);
});
console.log(adjustedTemps); // [42, 55, 60, 70]
console.log(tempArray); // [32, 45, 50, 60]Short Answer
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