GitHub - MWaqasHussain-dev/es6: // ARRAY ITERATION JS // *** For Each *** // Iterate over each item of the array [1,2,3,4].forEach((item,index)=> { console.log(item,index); // Expected output: // 1 0 // 2 1 // 3 2 // 4 3 }) // *** Map *** // Iterate over each item of array and creates a new array const single = [1,2,3,4] const double = single.map(item => item*2) console.log(double); // Expected output: [2, 4, 6, 8] // *** Filter *** // creates a new array with all elements that pass the test implemented by the provided function. const array = [1,2,3,4] const filterArray = array.filter(item => item < 2) // values which pass the test " item < 2 " will be return and put in filterArray console.log(filterArray); // Expected output: [1] // *** Reduce *** // The reduce() method executes a reducer function (that you provide) // on each element of the array, resulting in single output value // Example 1 const sum = [1,2,3,4].reduce((result,item) => { return result + item },0); console.log(sum); // Expected output: 10 // Example 2 const arrayOfObj = [{value: 1},{value: 2},{value: 3},{value: 4}] const sumOfArrayOfObj = arrayOfObj.reduce((result,item)=>{ return result + item.value }, // initial value for result is 0, if value not provided // then first item of array({value:1}) will be result 0) console.log(sumOfArrayOfObj); // Expected output: 10 // *** Some *** // The some() method tests whether at least one element in // the array passes the test implemented by the provided function. // It returns true if, in the array, it finds an element for which // the provided function returns true; otherwise it returns false. // It doesn't modify the array. const hasNegativeNumber = [-1,2,3,4,5,6].some(item => item < 0) console.log(hasNegativeNumber); // Expected output: true // *** Every *** // The every() method tests whether all elements in the array pass the test // implemented by the provided function. It returns a Boolean value. const allNegativeNumber = [-1,2,3,4,5,6].every(item => item < 0) console.log(allNegativeNumber); // Expected output: false // *** Find *** // The find() method returns the value of the first element in the provided // array that satisfies the provided testing function. If no values satisfy // the testing function, undefined is returned. const objects = [{value: 1},{value: 2},{value: 3},{value: 4}] const found = objects.find(item => item.value > 1) console.log(found); // Expected output: {value: 2} // ** FindIndex ** // The findIndex() method returns the index of the first element in the array // that satisfies the provided testing function. Otherwise, it returns -1, // indicating that no element passed the test. const objects1 = [{value: 1},{value: 2},{value: 3},{value: 4}] const foundIndex = objects1.findIndex(item => item.value === 1) console.log(foundIndex); // Expected output: 0

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// ARRAY ITERATION JS // *** For Each *** // Iterate over each item of the array [1,2,3,4].forEach((item,index)=> { console.log(item,index); // Expected output: // 1 0 // 2 1 // 3 2 // 4 3 }) // *** Map *** // Iterate over each item of array and creates a new array const single = [1,2,3,4] const double = single.map(item => item*2) console.log(do…