index.md

jscodeshift: Refactor JS w/ JS

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https://hackmd.io/p/H1Hcn6da-

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Questions Here

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Please Pull My Plug On Time

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Prologue

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Scene I

Demo

AST Explorer

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Use Cases

• Reduce coding patterns in your codebase
• Change codebase as domain term changes
• Upgrade codebase as you learn more
• Provide codemods as your API upgrades

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Act I: Find

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Scene I

Find by astNodeType

AST Explorer

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Scene II

Find by filter

AST Explorer

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Act II: Replace

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Scene I

Modify nodes

AST Explorer

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Scene II

insertBefore

AST Explorer

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Scene III

replaceWith

AST Explorer

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Scene IV

ast-types

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Scene V

Tagged template literal

AST Explorer

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Act III: Test

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Scene I

defineTest

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Scene II

defineInlineTest

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Act IV: Extend

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Scene I

registerMethods

AST Explorer

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Scene II

registerMethods for AST node type

AST Explorer

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Epilogue

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Scene I

Is it safe?

As long as you have backups

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Scene II

Is there any API reference?

Yes

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Scene III

What's your name?

Folio

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Scene IV

What's her name?

Winnie

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Scene V

Why don't we use RegExp?

If you are not Chuck Norris. Then the seven angels who had the seven trumpets prepared to sound them. — Revelation 8.6

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Reference

• Evolving Complex Systems Incrementally
• Effective JavaScript Codemods
• facebook/jscodeshift Github
• benjamn/recast Github
• benjamn/ast-types Github
• cpojer/js-codemod Github
• jhgg/js-transforms Github

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Q&A