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July 6, 2016 14:20
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Redux: Writing a Counter Reducer with Tests
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| <!DOCTYPE html> | |
| <html> | |
| <head> | |
| <meta charset="utf-8"> | |
| <title>Getting Started with Redux</title> | |
| <script src="https://wzrd.in/standalone/expect@latest"></script> | |
| <script src="script.js"></script> | |
| </head> | |
| <body> | |
| </body> | |
| </html> |
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| // Open the console tab to see that the tests pass. | |
| // https://egghead.io/lessons/javascript-redux-writing-a-counter-reducer-with-tests | |
| // Reducer for the counter example | |
| const counter = (state = 0, action) => { | |
| switch(action.type) { | |
| case 'INCREMENT': | |
| return state + 1; | |
| case 'DECREMENT': | |
| return state - 1; | |
| default: | |
| return state; | |
| } | |
| } | |
| expect( | |
| counter(0, {type: 'INCREMENT'}) | |
| ).toEqual(1); | |
| expect( | |
| counter(1, {type: 'INCREMENT'}) | |
| ).toEqual(2); | |
| expect( | |
| counter(2, {type: 'DECREMENT'}) | |
| ).toEqual(1); | |
| expect( | |
| counter(1, {type: 'DECREMENT'}) | |
| ).toEqual(0); | |
| expect( | |
| counter(1, {type: 'UNKNOWN'}) | |
| ).toEqual(1); | |
| expect( | |
| counter(undefined, {}) | |
| ).toEqual(0); | |
| console.log('Tests passed!') |
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