lihai 8d6c751f49 feat: push | 2 år sedan | |
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index.js | 2 år sedan | |
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readme.md | 2 år sedan |
Install a transform to
require.extensions
that always runs last, even if additional extensions are added later.
The typical require extension looks something like this:
var myTransform = require('my-transform');
var oldExtension = require.extensions['.js'];
require.extensions['.js'] = function (module, filename) {
var oldCompile = module._compile;
module._compile = function (code, filename) {
code = myTransform(code);
module._compile = oldCompile;
module._compile(code, filename);
};
oldExtension(module, filename);
};
In almost all cases, that is sufficient and is the method that should be used (check out pirates
for an easy way to do it correctly). In rare cases you must ensure your transform remains the last one, even if other transforms are added later. For example, nyc
uses this module to ensure its transform is applied last so it can capture the final source-map information, and ensure any language extensions it can't understand are already transpiled (ES2015 via babel
for instance).
WARNING: You should be sure you actually need this, as it takes control away from the user. Your transform remains the last one applied, even as users continue to add more transforms. This is potentially confusing. Coverage libraries like nyc
(and istanbul
on which it relies) have valid reasons for doing this, but you should prefer conventional transform installation via pirates
.
References:
$ npm install --save append-transform
var appendTransform = require('append-transform');
var myTransform = require('my-transform');
appendTransform(function (code, filename) {
if (myTransform.shouldTransform(filename)) {
code = myTransform.transform(code);
}
return code;
});
Type: function(code: string, filename: string)
Required
A callback that modifies the incoming code
argument in some way, and returns the transformed result. filename
is provided to filter which files the transform applies to. If a transform should not manipulate a particular file, just return code
without modifying it. It is fairly common to avoid transforming files in node_modules
. In that case you may want to use node-modules-regexp
to help reliably detect node_modules
paths and avoid transforming them.
Type: string
Default: ".js"
The extension for the types of files this transform is capable of handling.
MIT © James Talmage