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| // Create keyed object from array | |
| // importance: 4 | |
| // Let’s say we received an array of users in the form {id:..., name:..., age:... }. | |
| // Create a function groupById(arr) that creates an object from it, with id as the key, and array items as values. | |
| // function groupById(users) { | |
| // return users.reduce((obj, user) => { | |
| // obj[user.id] = user; | |
| // return obj; | |
| // }, {}); | |
| // } | |
| let users = [ | |
| {id: 'john', name: "John Smith", age: 20}, | |
| {id: 'ann', name: "Ann Smith", age: 24}, | |
| {id: 'pete', name: "Pete Peterson", age: 31}, | |
| ]; | |
| let usersById = groupById(users); | |
| console.log(usersById); | |
| /* | |
| // after the call we should have: | |
| usersById = { | |
| john: {id: 'john', name: "John Smith", age: 20}, | |
| ann: {id: 'ann', name: "Ann Smith", age: 24}, | |
| pete: {id: 'pete', name: "Pete Peterson", age: 31}, | |
| } | |
| */ |
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