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Try improve crash course

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This commit is contained in:
Aaron Smith 2023-11-21 18:48:47 +00:00
parent c288cb92c4
commit 338c66ed57
11 changed files with 223 additions and 102 deletions
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20
docs/tut/crash-course/9-derived-source.md
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@ -29,13 +29,10 @@ local text = function()
return "count: " .. tostring(count())
end
effect(function()
text() -- prints "ran"
end)
effect(function() text() end)
effect(function() text() end)
effect(function()
text() -- prints "ran" again
end)
source(1) -- prints "ran" x2
```
To avoid this, you can use `derive()` to derive a new source instead. This will
@ -55,16 +52,13 @@ local text = derive(function()
return "count: " .. tostring(count())
end)
effect(function()
text() -- prints "ran"
end)
effect(function() text() end)
effect(function() text() end)
effect(function()
text() -- does not print, returns cached value
end)
source(1) -- prints "ran" x1
```
`derive()` must also be used within a root reactive scope, just like `effect()`.
`derive()` must also be called within a reactive scope, just like `effect()`.
If the recalculated value is the same as the old value, the derived source will
not rerun the effects using it.