This commit is contained in:
Peli de Halleux 2016-07-26 13:52:01 -07:00
commit 6f00384891
4 changed files with 65 additions and 14 deletions

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@ -27,5 +27,10 @@ Visit the cards below to starting programming JavaScript and TypeScript with the
},{
"name": "Classes",
"url": "/js/classes"
}]
},{
"name": "FAQ",
"url": "/js/faq"
}
]
```

58
docs/js/faq.md Normal file
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@ -0,0 +1,58 @@
# Frequently asked questions
# What is the language supported for the micro:bit?
For the micro:bit, we support a "static" subset of TypeScript (itself a superset of JavaScript):
## Supported language features
* variables with `let`, `const`, and `var`
* functions with lexical scoping and recursion
* top-level code in the file; hello world really is `console.log("Hello world")`
* `if ... else if ... else` statements
* `while` and `do ... while` loops
* `for(;;)` loops (see below about `for ... in/of`)
* `break/continue`; also with labeled loops
* `switch` statement (on numbers only)
* `debugger` statement for breakpoints
* conditional operator `? :`; lazy boolean operators
* namespaces (a form of modules)
* all arithmetic operators (including bitwise operators); note that in microcontroller targets
all arithmetic is performed on integers, also when simulating in the browser
* strings (with a few common methods)
* [string templates](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Template_literals) (`` `x is ${x}` ``)
* arrow functions `() => ...`
* classes with fields, methods and constructors; `new` keyword
* array literals `[1, 2, 3]`
* enums
## Unsupported language features
We generally stay away from the more dynamic parts of JavaScript.
Things you may miss and we may implement:
* exceptions (`throw`, `try ... catch`, `try ... finally`)
* `for ... of` statements
* object literals `{ foo: 1, bar: "two" }`
* method-like properties (get/set accessors)
* class inheritance
For JS-only targets we may implement the following:
* regular expressions
* classes implementing interfaces
Things that we are not very likely to implement:
* file-based modules (`import * from ...`, `module.exports` etc); we do support namespaces
* spread operator
* `yield` expression and ``function*``
* `await` expression and `async function`
* `typeof` expression
* tagged templates ``tag `text ${expression} more text` ``; regular templates are supported
* binding with arrays or objects: `let [a, b] = ...; let { x, y } = ...`
* `with` statement
* `eval`
* `delete` statement
* `for ... in` statements
* JSX (HTML as part of JavaScript)

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@ -35,7 +35,7 @@ basic.showNumber(1);
basic.showNumber(2);
```
## The empty statement
### The empty statement
In JavaScript, there is the concept of an *empty statement*, which is whitespace followed by
a semicolon in the context where a statement is expected.

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@ -22,15 +22,3 @@ control.inBackground(() => {
});
```
## Advanced
```namespaces
devices.tellCameraTo(MesCameraEvent.TakePhoto);
bluetooth.onBluetoothConnected(() => {});
```
```package
microbit-devices
microbit-bluetooth
```