Docs: Reactivity

[NigelBreslaw]

No description provided.

[NigelBreslaw]

Maybe Monday have a call about this and hash out if that react.js section should go in and how it could be better refined? Thinking is that a ton of people are familiar with React and this would help them understand Slint and be less confused by it. It also intentionally dunks on some of the issues in React that catch out all beginners. I should also add in a section on 'useEffect' and how to manage side effects and how Slint is also much simpler there.

[tronical]

The colon suggest that there will be a list of ways, but.... there isn't. If the list is supposed to be the following headings, how about: "Slint differs from React.js in several key ways. The following sections discuss these differences."

[tronical]

Title caps here

Suggested change

	### Component life cycle management
	### Component Life Cycle Management

[tronical]

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	To manage performance careful use of useMemo and useCallback are needed to avoid unnecessary re-renders. Even
	To manage performance, careful use of `useMemo()` and `useCallback()` are needed to avoid unnecessary re-renders. Even

[tronical]

Suggested change

	Slint is much simpler. Components update, but they are not destroyed and recreated. There is no equivlant of
	useMemo and useCallback as they are unnecessary.
	Slint is much simpler: Components update, but they are not destroyed and recreated. There is no equivlant of
	`useMemo()` and `useCallback()` as they are unnecessary.

[tronical]

Suggested change

	React.js refers to properties that update and re-render the component as state. They are opt in and by
	React.js refers to properties that update and re-render the component as state. They are opt-in and by

[tronical]

Suggested change

	on the 'currentCount' value returned by setCount is used to update the values. As using `setCount(count + 1)`
	on the `currentCount` value returned by `setCount()` is used to update the values. As using `setCount(count + 1)`

[tronical]

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	in Slint is reactive by default the property is declared in one single way. The language has strong types and for
	in Slint is reactive by default, the property is declared in one single way. The language has strong types and for

[tronical]

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	As the name suggests Reactivity is all about parts of the user interface automatically updating or 'reacting'
	As the name suggests, reactivity is all about parts of the user interface automatically updating or 'reacting'

[tronical]

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	## Performance
	From a performance perspective Slint works out what properties are changed. It then finds all the expressions
	that depend on that value. These dependencies are then re-evaluated based on the new values and the UI will update.
	## Performance
	From a performance perspective, Slint works out what properties are changed. It then finds all the expressions
	that depend on that value. These dependencies are then re-evaluated based on the new values and the UI updates.

[tronical]

Suggested change

	## Property Expressions
	Expressions can vary in complexity:
	## Property Expressions
	Expressions can vary in complexity: