Whether you choose some or every is entirely dependent on what you believe to be the most readable. Syntax: myMap.

If you want the benefits of the return value or somehow you don’t want to change the original array then proceed with the map() otherwise if you are just interested to iterate or perform the non-transformation process on the array, forEach() could be the better choice.You can see that the function returns true when it reaches the “Steph” name and breaks the loop. The Map.forEach method is used to loop over the map with the given function and executes the given function over each key-value pair. With the map() method, we can chain other methods like, reduce(),sort() etc.Ĭonclusion: As they are working with very few differences, also the execution speed is not significant to consider so it is time to think about, which one to choose. The forEach() method doesn’t return anything hence the method chaining technique cannot be applied here. The map() method returns the newly created array according to the provided callback function. The forEach() method returns “ undefined“. The map() method returns an entirely new array. The forEach() method does not returns a new array based on the given array.

ĭifferences between forEach() and map() methods: Output: Here the map method returns an array that invokes the next instance method and which later provides the final returnValue(reverse of the invoking array). ISRO CS Syllabus for Scientist/Engineer Exam.ISRO CS Original Papers and Official Keys.arr (optional) - the array of the current elements. index (optional) - the index of the current element. GATE CS Original Papers and Official Keys The syntax of the forEach () method is: array.forEach (function(currentValue, index, arr)) Here, function (currentValue, index, arr) - a function to be run for each element of an array.

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For each loop in js