External Plugin

This is a third-party plugin. Please report issues in its Github Repository(opens new window)

# hardhat-watcher

Automatically run Hardhat actions when files change

# Installation

npm install hardhat-watcher

or

yarn add hardhat-watcher

Import the plugin in your hardhat.config.js:

require("hardhat-watcher");

Or if you are using TypeScript, in your hardhat.config.ts:

import "hardhat-watcher";

# Tasks

This plugin adds the watch task to Hardhat:

npx hardhat watch

# Configuration

This plugin extends the HardhatUserConfig's object with an optional watcher field. Every property of watcher is optional.

This is the complete type:

module.exports = {
  watcher: {
    [key: string]: { // key is the name for the watcherTask
      tasks?: (string | { command: string, params?: { [key: string] => any } })[]; // Every task of the hardhat runtime is supported (including other plugins!)
      files?: string[]; // Files, directories or glob patterns to watch for changes. (defaults to `[config.paths.sources]`, which itself defaults to the `contracts` dir)
      verbose?: boolean; // Turn on for extra logging
    }
  }
};

# Usage

The most basic use case, which is simply compiling your files on change, is accomplished very easily with this config:

module.exports = {
  watcher: {
    compilation: {
      tasks: ["compile"],
    }
  },
}

and subsequently running npx hardhat watch compilation

A bit more involved and showcasing the use of parameters for tasks and defining multiple watcher tasks:

module.exports = {
  watcher: {
    compilation: {
      tasks: ["compile"],
      files: ["./contracts"],
      verbose: true,
    },
    ci: {
      tasks: ["clean", { command: "compile", params: { quiet: true } }, { command: "test", params: { noCompile: true, testFiles: ["testfile.ts"] } } ],
    }
  },
}

Run npx hardhat watch ci to clean, compile and test on every file change, or run npx hardhat watch compilation to compile.

# Positional arguments

Positional arguments are provided in the same way as "normal" arguments (check out the testFiles argument in the example above, it's a positional argument). In order to find the name of a positional argument, simply run yarn hardhat <YOUR_COMMAND> --help. This is an example output for the test command:

Hardhat version 2.0.2

Usage: hardhat [GLOBAL OPTIONS] test [--no-compile] [...testFiles]

OPTIONS:

  --no-compile  Don't compile before running this task 

POSITIONAL ARGUMENTS:

  testFiles     An optional list of files to test (default: [])

test: Runs mocha tests

For global options help run: hardhat help
```