chrisnajman / meme-generator

Built from Scrimba's 'Build a meme generator' tutorials. Dynamically add text to the top and bottom of the image. Click the button to generate a new image.

React Meme Generator

• Input text to the 'Top text' and 'Bottom text' inputs to generate text above and below the image.
• Click the button to generate a new image.

Note

No data is saved.

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Scrimba Course Link

• Build a Meme Generator

Note

(Free) subscription and login required to follow the course.

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useEffect()

What is a "side effect" in React? What are some examples?

• Any code that affects an outside system, e.g.
• local storage, API, websockets, two states to keep in sync.

What is NOT a "side effect" in React? Examples?

Anything that React is in charge of, e.g.

• Maintaining state,
• keeping the UI in sync with the data,
• rendering DOM elements.

When does React run the useEffect function?

• As soon as the component loads (first render).
• On every re-render of the component (assuming no dependencies array).

When does it NOT run the useEffect function?

• when the values of the dependencies in the array stay the same between renders.

What is the "dependencies array"?

• Second parameter to the useEffect function.
• A way for React to know whether it should re-run the effect function.

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Testing

Tested on Windows 10 with:

• Chrome
• Firefox
• Microsoft Edge

Page tested in both browser and device views.