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Maribeth Moffatt
34 lines
1.4 KiB
Plaintext
34 lines
1.4 KiB
Plaintext
---
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slug: /codelabs/custom-generator/generating-a-stack/index.html
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description: How to generate code for the blocks in a stack.
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---
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# Build a custom generator
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## 9. Generating a stack
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### The scrub_ function
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The `scrub_` function is called on every block from `blockToCode`. It takes in three arguments:
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- `block` is the current block.
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- `code` is the code generated for this block, which includes code from all attached value blocks.
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- `opt_thisOnly` is an optional `boolean`. If true, code should be generated for this block but no subsequent blocks.
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By default, `scrub_` simply returns the passed-in code. A common pattern is to override the function to also generate code for any blocks that follow the current block in a stack. In this case, the code will add commas and newlines between object members:
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```js
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jsonGenerator.scrub_ = function(block, code, thisOnly) {
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const nextBlock =
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block.nextConnection && block.nextConnection.targetBlock();
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if (nextBlock && !thisOnly) {
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return code + ',\n' + jsonGenerator.blockToCode(nextBlock);
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}
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return code;
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};
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```
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### Testing scrub_
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Create a stack of `member` blocks on the workspace. There should be generated code for all of the blocks, not just the first one.
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Next, add an `object` block and drag the `member` blocks into it. This case tests `statementToCode`, and should generate code for all of of the blocks. |