rollup
rollup-pluginutils
A set of functions commonly used by Rollup plugins.
Installation
npm install --save rollup-pluginutilsUsage
addExtension
import { addExtension } from 'rollup-pluginutils';
export default function myPlugin ( options = {} ) {
return {
resolveId ( code, id ) {
// only adds an extension if there isn't one already
id = addExtension( id ); // `foo` -> `foo.js`, `foo.js -> foo.js`
id = addExtension( id, '.myext' ); // `foo` -> `foo.myext`, `foo.js -> `foo.js`
}
};
}attachScopes
This function attaches Scope objects to the relevant nodes of an AST. Each Scope object has a scope.contains(name) method that returns true if a given name is defined in the current scope or a parent scope.
See rollup-plugin-inject or rollup-plugin-commonjs for an example of usage.
import { attachScopes } from 'rollup-pluginutils';
import { walk } from 'estree-walker';
export default function myPlugin ( options = {} ) {
return {
transform ( code ) {
const ast = this.parse( code );
let scope = attachScopes( ast, 'scope' );
walk( ast, {
enter ( node ) {
if ( node.scope ) scope = node.scope;
if ( !scope.contains( 'foo' ) ) {
// `foo` is not defined, so if we encounter it,
// we assume it's a global
}
},
leave ( node ) {
if ( node.scope ) scope = scope.parent;
}
});
}
};
}createFilter
import { createFilter } from 'rollup-pluginutils';
export default function myPlugin ( options = {} ) {
// `options.include` and `options.exclude` can each be a minimatch
// pattern, or an array of minimatch patterns, relative to process.cwd()
var filter = createFilter( options.include, options.exclude );
return {
transform ( code, id ) {
// if `options.include` is omitted or has zero length, filter
// will return `true` by default. Otherwise, an ID must match
// one or more of the minimatch patterns, and must not match
// any of the `options.exclude` patterns.
if ( !filter( id ) ) return;
// proceed with the transformation...
}
};
}If you want to resolve the patterns against a directory other than
process.cwd(), you can additionally pass a resolve option:
var filter = createFilter( options.include, options.exclude, {resolve: '/my/base/dir'} )If resolve is a string, then this value will be used as the base directory.
Relative paths will be resolved against process.cwd() first. If resolve is
false, then the patterns will not be resolved against any directory. This can
be useful if you want to create a filter for virtual module names.
makeLegalIdentifier
import { makeLegalIdentifier } from 'rollup-pluginutils';
makeLegalIdentifier( 'foo-bar' ); // 'foo_bar'
makeLegalIdentifier( 'typeof' ); // '_typeof'dataToEsm
Helper for treeshakable data imports
import { dataToEsm } from 'rollup-pluginutils';
const esModuleSource = dataToEsm({
custom: 'data',
to: ['treeshake']
}, {
compact: false,
indent: '\t',
preferConst: false,
objectShorthand: false,
namedExports: true
});
/*
Outputs the string ES module source:
export const custom = 'data';
export const to = ['treeshake'];
export default { custom, to };
*/extractAssignedNames
Extract the names of all assignment targets from patterns.
import { extractAssignedNames } from 'rollup-pluginutils';
import { walk } from 'estree-walker';
export default function myPlugin ( options = {} ) {
return {
transform ( code ) {
const ast = this.parse( code );
walk( ast, {
enter ( node ) {
if ( node.type === 'VariableDeclarator' ) {
const declaredNames = extractAssignedNames(node.id);
// do something with the declared names
// e.g. for `const {x, y: z} = ... => declaredNames = ['x', 'z']
}
}
});
}
};
}License
MIT