babel-plugin-prepend

Babel plugin that allows a statement to be prepended on files during the transformation.

Install

With npm do:

npm i babel-plugin-prepend --D

Usage

The plugin accepts 2 options:

• prepend: mandatory option that needs to contain the statement to be prepended during transformation
• accept: a filter function to accept or deny transformation on files based on the file name

The prepend option needs to contain 1 single statement.

If the accept option is not needed, the plugin can be added to .babelrc as follows:

{
    "plugins": [
        [
            "prepend",
            {
                "prepend": "var a = 1;"
            }
        ]
    ]
}

If the 'accept' option is needed, then the plugin needs to be added to babel.config.js as follows:

{
    plugins: [
        [
            prepend,
            {
                prepend: 'var a = 1;',
                accept: function (filename) {
                    return true;
                }
            }
        ]
    ];
}

Example

Input

var b = 2;

Output

var a = 1;
var b = 2;

Contributing

Feel free to submit pull requests. When adding anything new, please remember to update the tests file.

License

MIT © Marcos Pont