Manipulating Javascript Array with for-of
2 min readJul 21, 2022
1. Filtering an array with for-of
function filterArray( arrayList, callBackFunc){
const output = [];
for(const val of arrayList){
if(callBackFunc(val)){
output.push(val)
}
} return output}
filterArray(['','Mango','','Apple',''], str => str.length > 0)
2. Mapping an array with for-of
function mapArray(arrayList, callBackFunc){
const output = [];
for(const val of arrayList){
output.push(callBackFunc(val));
}
return output}mapArray([1,2,3], num => num + num);
3. Filtering and Mapping an array with for-of
function getSeriesTitles(cwSeries, minRating){ const output= []; for(const series of cwSeries){ if(series.rating >= minRating) result.push(series.title) } return output
}const cwSeries= [ { title: 'Arrow', rating: 8.8 }, { title: 'Flash', rating: 7.9 }, { title: 'Lucifer', rating: 8.1 }, { title: 'Legends of Tomorrow', rating: 8.5 }, { title: 'Super Girl', rating: 7.8 },
];
getSeriesTitles(cwSeries, 8);
4. Finding an item in an Array with for-of
function findInArray(arrayList,callBackFunc){ for(const[index,value] of arrayList.entries()){ if(callBackFunc(value)) return{index,value} } return undefined}findInArray(['','a','','bimbo','c','tao'],str=> str.length > 1);
5. Finding the average of the values in an array of objects with for-of
function averageStudentGrade(students){ let sumOfGrades = 0; for(const student of students){ sumOfGrades += student.grade; } return sumOfGrades / students.length; }const STUDENTS = [
{
id: 'qk4k4yif4a',
grade: 4.0,
},
{
id: 'r6vczv0ds3',
grade: 0.25,
},
{
id: '9s53dn6pbk',
grade: 1,
}];averageStudentGrade(STUDENTS);
6. Checking a condition with for-of
function everyArrayElement(arrayList,condtion){ for(const elem of arrayList){ if(!condtion(elem)){ return false } } return true;
}everyArrayElement(['a','','b'], str =>str.length > 1);
Thank you….