Install as command-line tool


npm install -g escut

Usage: escut selector command file.js

    # A CSS-like selector, see https://github.com/keeyip/esquery
    @selector

    @command json

    @command print

    @command quote-member

    @command quote-property

    @command remove

    # Rewrites code using a handlebars replacement string
    @command rewrite replacement

        # A handlebars replacement string
        @param replacement

            # Prints javascript for the given AST node
            @helper js node

                # An AST node
                @param node

            # Prints each node, separated by `, `
            @helper splat nodes

                # List of AST nodes
                @param nodes

        # Use `_.bind` instead of `Function.prototype.bind`
        @example
            @file.js ```y.bind(this, a, b, c)```
            @sh escut "CallExpression[callee.property.name=bind]" "rewrite _.bind({{js callee.object}}, {{splat arguments}})" file.js
            @output  ```_.bind(y, this, a, b, c)```

    @command yank

Design

Todo

• Use escope to do scope lookups
• Command to output callgraph
• Command to output scopes and variables as a tree
• Command to find unused variables
• Example that traces specific function calls
• Command to summarize jsdoc
• Command to create jsdoc annotations

References

spidermonkey AST

esquery

Tutorial

In the code below, suppose you want to rename about: to help:

// commands/quote-property.js
module.exports = {
    about: {
        arguments: '',
        description: '',
        examples: [
        ]
    },
    run: run
};
...

Solution:

escut "Property[key.name='about'] > .key" "rewrite help" commands/quote-property.js

Suppose you want to do this for each file below:

commands/
├── json.js
├── print.js
├── quote-member.js
├── quote-property.js
├── remove.js
├── rewrite
│   ├── helpers
│   │   ├── js.js
│   │   └── splat.js
│   └── index.js
└── yank.js

Solution:

# tree -- http://brewformulas.org/tree
# parallel -- http://brewformulas.org/parallel (not the one in http://brewformulas.org/moreutil)
# sponge -- http://brewformulas.org/moreutil
tree -f -i -n --noreport commands | grep .js$ | parallel "escut \"Property[key.name='about'] > .key\" \"rewrite help\" {} | sponge {}"

Cookbook

Rename an object property

Use _.bind() instead of Function.prototype.bind

Internals

__escutNewCode