buidler-preprocessor

This plugin allows to pre-preocess contract source code before compilation

Buidler preprocessor plugin.

What

This plugin allow you to specify a function that is executed on every line of all contracts so that you can pre-process the code.

A typical example (included) is to remove console.log for production ready contracts.

Note that this plugin do not touch the filesystem. It happens in memory.

Installation

npm install buidler-preprocessor

And add the following statement to your buidler.config.js:

usePlugin('buidler-preprocessor');

Required plugins

Nothing required

Tasks

No new tasks but it overrides the compile task.

Environment extensions

No extra fields added to the envirobment.

Configuration

This plugin extends the BuidlerConfig with one new field: preprocess

This field is an object with a field : eachLine that itself is a function that accept the BRE as argument and must return either a function or a promise to a function.

That function exepect a string as argument (a line of a contract) and must return a string.

Note that instead of returning (or resolving a function), it is possible to return undefined to skip the preprocessing entirely.

Basic example that add a comment on each line:

usePlugin('buidler-preprocessor');
module.exports = {
  preprocess: {
    eachLine: (bre) => (line) => line + '// comment at the end of each line',
  },
};

The plugin comes also with a preprocess function to remove console.log (achieving the same thing as this plugin but without changing the files )

You can use it as follow :

usePlugin('buidler-preprocessor');
const {removeConsoleLog} = require('buidler-preprocessor');
module.exports = {
  preprocess: {
    eachLine: removeConsoleLog((bre) => bre.network.name !== 'buidlerevm' && bre.network.name !== 'localhost'),
  },
};

In this example the preprocessing do not happen when used against buidlerevm (testing) or localhost

Usage

There are no additional steps you need to take for this plugin to work.

TypeScript support

You need to add this to your tsconfig.json's files array: "node_modules/buidler-preprocessor/src/type-extensions.d.ts"