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Use ES6 for code in extension docs

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Christopher Willis-Ford 2019-04-05 15:00:09 -07:00
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docs/extensions.md
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@ -9,8 +9,9 @@ wiki](https://github.com/LLK/docs/wiki/Extensions).
## Types of Extensions
There are four types of extensions that can define everything from the Scratch's core library (such as the "Looks" and
"Operators" categories) to unofficial extensions that can be loaded from a remote URL. Unofficial extensions are not
yet supported.
"Operators" categories) to unofficial extensions that can be loaded from a remote URL.
**Scratch 3.0 does not yet support unofficial extensions.**
For more details, see [this Extensions page on the wiki](https://github.com/LLK/docs/wiki/Extensions).
@ -22,6 +23,15 @@ For more details, see [this Extensions page on the wiki](https://github.com/LLK/
| Sandboxed | X | X | √ | √ |
| Can save projects to community | √ | √ | √ | X |
## JavaScript Environment
Most Scratch 3.0 is written using JavaScript features not yet commonly supported by browsers. For compatibility we
transpile the code to ES5 before publishing or deploying. Any extension included in the `scratch-vm` repository may
use ES6+ features and may use `require` to reference other code within the `scratch-vm` repository.
Unofficial extensions must be self-contained. Authors of unofficial extensions are responsible for ensuring browser
compatibility for those extensions, including transpiling if necessary.
## Translation
Scratch extensions use the [ICU message format](http://userguide.icu-project.org/formatparse/messages) to handle
@ -46,12 +56,17 @@ Scratch extensions are defined as a single Javascript class which accepts either
across a well defined worker boundary (i.e. the sandbox).
```js
var SomeBlocks = function (runtimeProxy) {
/**
* A proxy to communicate with the Scratch 3.0 runtime across a worker boundary.
* @type {Runtime}
*/
this.runtime = runtimeProxy;
class SomeBlocks {
constructor (runtime) {
/**
* Store this for later communication with the Scratch VM runtime.
* If this extension is running in a sandbox then `runtime` is an async proxy object.
* @type {Runtime}
*/
this.runtime = runtime;
}
// ...
}
```
@ -59,260 +74,271 @@ All extensions must define a function called `getInfo` which returns an object t
render both the blocks and the extension itself.
```js
SomeBlocks.prototype.getInfo = function () {
return {
id: 'someBlocks',
name: 'Some Blocks',
blocks: [
{
opcode: 'myReporter',
blockType: BlockType.REPORTER,
text: 'letter [LETTER_NUM] of [TEXT]',
arguments: {
LETTER_NUM: {
type: ArgumentType.STRING,
defaultValue: '1'
},
TEXT: {
type: ArgumentType.STRING,
defaultValue: 'text'
class SomeBlocks {
// ...
getInfo () {
return {
id: 'someBlocks',
name: 'Some Blocks',
blocks: [
{
opcode: 'myReporter',
blockType: BlockType.REPORTER,
text: 'letter [LETTER_NUM] of [TEXT]',
arguments: {
LETTER_NUM: {
type: ArgumentType.STRING,
defaultValue: '1'
},
TEXT: {
type: ArgumentType.STRING,
defaultValue: 'text'
}
}
}
}
]
};
};
]
};
}
// ...
}
```
Finally the extension must define a function for any "opcode" defined in the blocks. For example:
```js
SomeBlocks.prototype.myReporter = function (args) {
return args.TEXT.charAt(args.LETTER_NUM);
};
class SomeBlocks {
// ...
myReporter (args) {
return args.TEXT.charAt(args.LETTER_NUM);
};
// ...
}
```
## Annotated Example
```js
var SomeBlocks = function (runtimeProxy) {
class SomeBlocks {
constructor (runtime) {
/**
* Store this for later communication with the Scratch VM runtime.
* If this extension is running in a sandbox then `runtime` is an async proxy object.
* @type {Runtime}
*/
this.runtime = runtime;
}
/**
* A proxy to communicate with the Scratch 3.0 runtime across a worker boundary.
* @type {Runtime}
* @return {object} This extension's metadata.
*/
this.runtime = runtimeProxy;
};
getInfo () {
return {
// Required: the machine-readable name of this extension.
// Will be used as the extension's namespace.
id: 'someBlocks',
/**
* @return {object} This extension's metadata.
*/
SomeBlocks.prototype.getInfo = function () {
return {
// Required: the machine-readable name of this extension.
// Will be used as the extension's namespace.
id: 'someBlocks',
// Optional: the human-readable name of this extension as string.
// This and any other string to be displayed in the Scratch UI may either be
// a string or a call to `formatMessage`; a plain string will not be
// translated whereas a call to `formatMessage` will connect the string
// to the translation map (see below). The `formatMessage` call is
// similar to `formatMessage` from `react-intl` in form, but will actually
// call some extension support code to do its magic. For example, we will
// internally namespace the messages such that two extensions could have
// messages with the same ID without colliding.
// See also: https://github.com/yahoo/react-intl/wiki/API#formatmessage
name: formatMessage({
id: 'extensionName',
defaultMessage: 'Some Blocks',
description: 'Extension name'
}),
// Optional: the human-readable name of this extension as string.
// This and any other string to be displayed in the Scratch UI may either be
// a string or a call to `formatMessage`; a plain string will not be
// translated whereas a call to `formatMessage` will connect the string
// to the translation map (see below). The `formatMessage` call is
// similar to `formatMessage` from `react-intl` in form, but will actually
// call some extension support code to do its magic. For example, we will
// internally namespace the messages such that two extensions could have
// messages with the same ID without colliding.
// See also: https://github.com/yahoo/react-intl/wiki/API#formatmessage
name: formatMessage({
id: 'extensionName',
defaultMessage: 'Some Blocks',
description: 'Extension name'
}),
// Optional: URI for a block icon, to display at the edge of each block for this
// extension. Data URI OK.
// TODO: what file types are OK? All web images? Just PNG?
blockIconURI: 'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAkAAAAFCAAAAACyOJm3AAAAFklEQVQYV2P4DwMMEMgAI/+DEUIMBgAEWB7i7uidhAAAAABJRU5ErkJggg==',
// Optional: URI for a block icon, to display at the edge of each block for this
// extension. Data URI OK.
// TODO: what file types are OK? All web images? Just PNG?
blockIconURI: 'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAkAAAAFCAAAAACyOJm3AAAAFklEQVQYV2P4DwMMEMgAI/+DEUIMBgAEWB7i7uidhAAAAABJRU5ErkJggg==',
// Optional: URI for an icon to be displayed in the blocks category menu.
// If not present, the menu will display the block icon, if one is present.
// Otherwise, the category menu shows its default filled circle.
// Data URI OK.
// TODO: what file types are OK? All web images? Just PNG?
menuIconURI: 'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAkAAAAFCAAAAACyOJm3AAAAFklEQVQYV2P4DwMMEMgAI/+DEUIMBgAEWB7i7uidhAAAAABJRU5ErkJggg==',
// Optional: URI for an icon to be displayed in the blocks category menu.
// If not present, the menu will display the block icon, if one is present.
// Otherwise, the category menu shows its default filled circle.
// Data URI OK.
// TODO: what file types are OK? All web images? Just PNG?
menuIconURI: 'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAkAAAAFCAAAAACyOJm3AAAAFklEQVQYV2P4DwMMEMgAI/+DEUIMBgAEWB7i7uidhAAAAABJRU5ErkJggg==',
// Optional: Link to documentation content for this extension.
// If not present, offer no link.
docsURI: 'https://....',
// Optional: Link to documentation content for this extension.
// If not present, offer no link.
docsURI: 'https://....',
// Required: the list of blocks implemented by this extension,
// in the order intended for display.
blocks: [
{
// Required: the machine-readable name of this operation.
// This will appear in project JSON.
opcode: 'myReporter', // becomes 'someBlocks.myReporter'
// Required: the list of blocks implemented by this extension,
// in the order intended for display.
blocks: [
{
// Required: the machine-readable name of this operation.
// This will appear in project JSON.
opcode: 'myReporter', // becomes 'someBlocks.myReporter'
// Required: the kind of block we're defining, from a predefined list:
// 'command' - a normal command block, like "move {} steps"
// 'reporter' - returns a value, like "direction"
// 'Boolean' - same as 'reporter' but returns a Boolean value
// 'hat' - starts a stack if its value is truthy
// 'conditional' - control flow, like "if {}" or "if {} else {}"
// A 'conditional' block may return the one-based index of a branch to
// run, or it may return zero/falsy to run no branch.
// 'loop' - control flow, like "repeat {} {}" or "forever {}"
// A 'loop' block is like a conditional block with two differences:
// - the block is assumed to have exactly one child branch, and
// - each time a child branch finishes, the loop block is called again.
blockType: 'reporter',
// Required: the kind of block we're defining, from a predefined list:
// 'command' - a normal command block, like "move {} steps"
// 'reporter' - returns a value, like "direction"
// 'Boolean' - same as 'reporter' but returns a Boolean value
// 'hat' - starts a stack if its value is truthy
// 'conditional' - control flow, like "if {}" or "if {} else {}"
// A 'conditional' block may return the one-based index of a branch to
// run, or it may return zero/falsy to run no branch.
// 'loop' - control flow, like "repeat {} {}" or "forever {}"
// A 'loop' block is like a conditional block with two differences:
// - the block is assumed to have exactly one child branch, and
// - each time a child branch finishes, the loop block is called again.
blockType: 'reporter',
// Required for conditional blocks, ignored for others: the number of
// child branches this block controls. An "if" or "repeat" block would
// specify a branch count of 1; an "if-else" block would specify a
// branch count of 2.
// TODO: should we support dynamic branch count for "switch"-likes?
branchCount: 0,
// Required for conditional blocks, ignored for others: the number of
// child branches this block controls. An "if" or "repeat" block would
// specify a branch count of 1; an "if-else" block would specify a
// branch count of 2.
// TODO: should we support dynamic branch count for "switch"-likes?
branchCount: 0,
// Optional, default false: whether or not this block ends a stack.
// The "forever" and "stop all" blocks would specify true here.
terminal: true,
// Optional, default false: whether or not this block ends a stack.
// The "forever" and "stop all" blocks would specify true here.
terminal: true,
// Optional, default false: whether or not to block all threads while
// this block is busy. This is for things like the "touching color"
// block in compatibility mode, and is only needed if the VM runs in a
// worker. We might even consider omitting it from extension docs...
blockAllThreads: false,
// Optional, default false: whether or not to block all threads while
// this block is busy. This is for things like the "touching color"
// block in compatibility mode, and is only needed if the VM runs in a
// worker. We might even consider omitting it from extension docs...
blockAllThreads: false,
// Required: the human-readable text on this block, including argument
// placeholders. Argument placeholders should be in [MACRO_CASE] and
// must be [ENCLOSED_WITHIN_SQUARE_BRACKETS].
text: formatMessage({
id: 'myReporter',
defaultMessage: 'letter [LETTER_NUM] of [TEXT]',
description: 'Label on the "myReporter" block'
}),
// Required: the human-readable text on this block, including argument
// placeholders. Argument placeholders should be in [MACRO_CASE] and
// must be [ENCLOSED_WITHIN_SQUARE_BRACKETS].
text: formatMessage({
id: 'myReporter',
defaultMessage: 'letter [LETTER_NUM] of [TEXT]',
description: 'Label on the "myReporter" block'
}),
// Required: describe each argument.
// Argument order may change during translation, so arguments are
// identified by their placeholder name. In those situations where
// arguments must be ordered or assigned an ordinal, such as interaction
// with Scratch Blocks, arguments are ordered as they are in the default
// translation (probably English).
arguments: {
// Required: the ID of the argument, which will be the name in the
// args object passed to the implementation function.
LETTER_NUM: {
// Required: type of the argument / shape of the block input
type: 'number',
// Optional: the default value of the argument
default: 1
},
// Required: the ID of the argument, which will be the name in the
// args object passed to the implementation function.
TEXT: {
// Required: type of the argument / shape of the block input
type: 'string',
// Required: describe each argument.
// Argument order may change during translation, so arguments are
// identified by their placeholder name. In those situations where
// arguments must be ordered or assigned an ordinal, such as interaction
// with Scratch Blocks, arguments are ordered as they are in the default
// translation (probably English).
arguments: {
// Required: the ID of the argument, which will be the name in the
// args object passed to the implementation function.
LETTER_NUM: {
// Required: type of the argument / shape of the block input
type: 'number',
// Optional: the default value of the argument
default: formatMessage({
id: 'myReporter.TEXT_default',
defaultMessage: 'text',
description: 'Default for "TEXT" argument of "myReporter"'
})
}
default: 1
},
// Required: the ID of the argument, which will be the name in the
// args object passed to the implementation function.
TEXT: {
// Required: type of the argument / shape of the block input
type: 'string',
// Optional: the default value of the argument
default: formatMessage({
id: 'myReporter.TEXT_default',
defaultMessage: 'text',
description: 'Default for "TEXT" argument of "myReporter"'
})
}
},
// Required: the function implementing this block.
func: 'myReporter',
// Optional: list of target types for which this block should appear.
// If absent, assume it applies to all builtin targets -- that is:
// ['sprite', 'stage']
filter: ['someBlocks.wedo2', 'sprite', 'stage']
},
// Required: the function implementing this block.
func: 'myReporter',
// Optional: list of target types for which this block should appear.
// If absent, assume it applies to all builtin targets -- that is:
// ['sprite', 'stage']
filter: ['someBlocks.wedo2', 'sprite', 'stage']
},
{
// Another block...
}
],
// Optional: define extension-specific menus here.
menus: {
// Required: an identifier for this menu, unique within this extension.
menuA: [
// Static menu: list items which should appear in the menu.
{
// Required: the value of the menu item when it is chosen.
value: 'itemId1',
// Optional: the human-readable label for this item.
// Use `value` as the text if this is absent.
text: formatMessage({
id: 'menuA_item1',
defaultMessage: 'Item One',
description: 'Label for item 1 of menu A'
})
},
// The simplest form of a list item is a string which will be used as
// both value and text.
'itemId2'
// Another block...
}
],
// Dynamic menu: returns an array as above.
// Called each time the menu is opened.
menuB: 'getItemsForMenuB'
},
// Optional: define extension-specific menus here.
menus: {
// Required: an identifier for this menu, unique within this extension.
menuA: [
// Static menu: list items which should appear in the menu.
{
// Required: the value of the menu item when it is chosen.
value: 'itemId1',
// Optional: translations
translation_map: {
de: {
'extensionName': 'Einige Blöcke',
'myReporter': 'Buchstabe [LETTER_NUM] von [TEXT]',
'myReporter.TEXT_default': 'Text',
'menuA_item1': 'Artikel eins',
// Optional: the human-readable label for this item.
// Use `value` as the text if this is absent.
text: formatMessage({
id: 'menuA_item1',
defaultMessage: 'Item One',
description: 'Label for item 1 of menu A'
})
},
// Dynamic menus can be translated too
'menuB_example': 'Beispiel',
// The simplest form of a list item is a string which will be used as
// both value and text.
'itemId2'
],
// This message contains ICU placeholders (see `myReporter()` below)
'myReporter.result': 'Buchstabe {LETTER_NUM} von {TEXT} ist {LETTER}.'
// Dynamic menu: returns an array as above.
// Called each time the menu is opened.
menuB: 'getItemsForMenuB'
},
it: {
// ...
}
},
// Optional: list new target type(s) provided by this extension.
targetTypes: [
'wedo2', // automatically transformed to 'someBlocks.wedo2'
'speech' // automatically transformed to 'someBlocks.speech'
]
// Optional: translations
translation_map: {
de: {
'extensionName': 'Einige Blöcke',
'myReporter': 'Buchstabe [LETTER_NUM] von [TEXT]',
'myReporter.TEXT_default': 'Text',
'menuA_item1': 'Artikel eins',
// Dynamic menus can be translated too
'menuB_example': 'Beispiel',
// This message contains ICU placeholders (see `myReporter()` below)
'myReporter.result': 'Buchstabe {LETTER_NUM} von {TEXT} ist {LETTER}.'
},
it: {
// ...
}
},
// Optional: list new target type(s) provided by this extension.
targetTypes: [
'wedo2', // automatically transformed to 'someBlocks.wedo2'
'speech' // automatically transformed to 'someBlocks.speech'
]
};
};
};
/**
* Implement myReporter.
* @param {object} args - the block's arguments.
* @property {string} MY_ARG - the string value of the argument.
* @returns {string} a string which includes the block argument value.
*/
SomeBlocks.prototype.myReporter = function (args) {
// This message contains ICU placeholders, not Scratch placeholders
const message = formatMessage({
id: 'myReporter.result',
defaultMessage: 'Letter {LETTER_NUM} of {TEXT} is {LETTER}.',
description: 'The text template for the "myReporter" block result'
});
/**
* Implement myReporter.
* @param {object} args - the block's arguments.
* @property {string} MY_ARG - the string value of the argument.
* @returns {string} a string which includes the block argument value.
*/
myReporter (args) {
// This message contains ICU placeholders, not Scratch placeholders
const message = formatMessage({
id: 'myReporter.result',
defaultMessage: 'Letter {LETTER_NUM} of {TEXT} is {LETTER}.',
description: 'The text template for the "myReporter" block result'
});
// Note: this implementation is not Unicode-clean; it's just here as an example.
const result = args.TEXT.charAt(args.LETTER_NUM);
// Note: this implementation is not Unicode-clean; it's just here as an example.
const result = args.TEXT.charAt(args.LETTER_NUM);
return message.format({
LETTER_NUM: args.LETTER_NUM,
TEXT: args.TEXT,
LETTER: result
});
};
return message.format({
LETTER_NUM: args.LETTER_NUM,
TEXT: args.TEXT,
LETTER: result
});
};
}
```