map
const names = ["Peter", "Nick", "Dagniel"]; ///convert an array of elements to an array of objects, with each object containing a 'firstname' prop that is mapped to the names[i] value.
const mapped = names.map(function(name) {
return {
firstname: name
}
})
mapped
///Map creates a new array that is the SAME length as the original. Uses the return value to build up the new array.
const integers = ["1", "2", "3", "4", "5"];
const mapped = integers.map(x => Number(x));
///Pull only active users.
const items = [
{
active: true,
firstName: 'Peter', ///add an \`active\` prop to each person.
lastName: 'Schussheim'
},
{
active: true,
firstName: 'Nicky',
lastName: 'Cat'
},
{
active: false,
firstName: 'Badger',
lastName: 'Cat'
}
];
const mapped = items
.filter(x => x.active)
.map(x => x.firstName);
function createLi(items) {
const listElements = items.map(x => ` <li>${x}</li>`).join('\n');
return `<ul>\n${listElements}\n</ul>`;
}
///Take an array of objects and pull off a particular value from each object.
const people = [
{
firstName: 'Peter',
lastName: 'Schussheim'
},
{
firstName: 'Nicky',
lastName: 'Cat'
}
];
var items = ["Binky", "Kevin"];
function createLi(items) {
const listElements = items.map(x => ` <li>${x}</li>`).join('\n');
return `<ul>\n${listElements}\n</ul>`;
}
var list = createLi(items);
const mapped = people.map(x => x.firstName);
///Add fields onto objects to better suite a particular application.
const people = [
{
firstName: 'Peter',
lastName: 'Schussheim'
},
{
firstName: 'Nicky',
lastName: 'Cat'
}
];
const mapped = people.map(x => {
return {
firstName: x.firstName,
lastName: x.lastName,
fullName: x.firstName + ' ' + x.lastName
};
});
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