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Artigos | Array.reduce - O canivete suíço da programação funcional | Array multidimensional
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| const users = [ | |
| { | |
| name: 'User #1', | |
| bookmarks: [ | |
| { title: 'Movie #1', id: 1 }, | |
| { title: 'Movie #6', id: 6 }, | |
| { title: 'Movie #3', id: 3 }, | |
| ] | |
| }, | |
| { | |
| name: 'User #2', | |
| bookmarks: [ | |
| { title: 'Movie #1', id: 1 }, | |
| { title: 'Movie #4', id: 4 }, | |
| { title: 'Movie #6', id: 6 }, | |
| { title: 'Movie #2', id: 2 }, | |
| ] | |
| } | |
| ]; | |
| const bookmarks = users | |
| .map(user => user.bookmarks) /* from: [ { #: [{...}] }, { #: [{...}] } ] */ | |
| .reduce((bookmarks, movies) => { /* to: [ [{...}], [{...}] ] */ | |
| return bookmarks | |
| .concat(movies.filter((movie) => { | |
| return bookmarks | |
| .map(movie => movie.id) | |
| .indexOf(movie.id) === -1; | |
| })); | |
| }, []); /* from: [ [{...}], [{...}] ] */ | |
| /* to: [ {...}, {...} ] */ | |
| /* | |
| #bookmarks | |
| [ | |
| { title: 'Movie #1', id: 1 }, | |
| { title: 'Movie #6', id: 6 }, | |
| { title: 'Movie #3', id: 3 }, | |
| { title: 'Movie #4', id: 4 }, | |
| { title: 'Movie #2', id: 2 }, | |
| ] | |
| */ |
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