Created
September 10, 2018 11:20
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example for how javascript callback works .....
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| const users = [ | |
| 'Jack Howton', | |
| 'Natividad Claussen', | |
| 'Jasper Egner', | |
| 'Adella Troxell', | |
| 'Edda Methvin', | |
| 'Aileen Chipley', | |
| 'Kellee Viles' | |
| ]; | |
| const petNames = { | |
| Jack: 'Jackson', | |
| Natividad: 'Navi', | |
| Jasper: 'Jas', | |
| Adella: 'Adele', | |
| Edda: 'Ed', | |
| Aileen: 'Ail', | |
| Kellee: 'Kely' | |
| } | |
| const getUsers = (callback) => { | |
| setTimeout(() => { | |
| callback(users); | |
| }, 1000); | |
| }; | |
| const getPetName = (firstName, callback) => { | |
| setTimeout(() => { | |
| callback(petNames[firstName]); | |
| }, 1000); | |
| }; | |
| const getPetNames = (firstNames, callback) => { | |
| setTimeout(() => { | |
| const pNames = firstNames.map((firstName) => petNames[firstName]) | |
| callback(pNames); | |
| }, 1000); | |
| }; | |
| const getFirstName = (name, callback) => { | |
| setTimeout(() => { | |
| const firstName = name.split(' ')[0]; | |
| callback(firstName); | |
| }, 1000); | |
| } | |
| const getFirstNames = (names, callback) => { | |
| setTimeout(() => { | |
| const firstNames = names.map((name) => name.split(' ')[0]); | |
| callback(firstNames); | |
| }) | |
| }; | |
| const moreThanlength = (name, length) => { | |
| return (name.length > length); | |
| } | |
| // get users | |
| getUsers((users) => { | |
| // get first names from provided users | |
| getFirstNames(users, (firstNames) => { | |
| // get pet names from provided first names | |
| getPetNames(firstNames, (petNames) => { | |
| // get pet names with more than 5 character | |
| const petNameMoreThan5Char = petNames.filter((petNames) => moreThanlength(petNames, 4)); | |
| console.log(petNameMoreThan5Char); | |
| }); | |
| }); | |
| }); | |
| // get users | |
| getUsers((users) => { | |
| // map each users to get name | |
| users.map(name => { | |
| // get first name of provided name | |
| getFirstName(name, (firstName) => { | |
| // get pet name of provided first name | |
| getPetName(firstName, (petName) => { | |
| console.log(petName); | |
| }); | |
| }); | |
| }); | |
| }); |
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