How check if Vue is in development mode?

In Vue.js, checking whether it is in development mode can be achieved through several methods, depending on the Vue version and build tools you are using. Here are some common approaches:

1. Checking via process.env.NODE_ENV

In Vue projects, you can check the current mode using the process.env.NODE_ENV environment variable, which is typically set by Webpack, Vue CLI, or other build tools. The value of process.env.NODE_ENV is usually set to development, production, or test.

javascript
if (process.env.NODE_ENV === 'development') {
  console.log('In development mode');
} else {
  console.log('Not in development mode');
}

2. Using Vue Configuration

In Vue 2.x, you can verify if development tools are enabled by checking Vue.config.devtools, which is typically active in development mode.

javascript
if (Vue.config.devtools) {
  console.log('Development mode');
} else {
  console.log('Production mode');
}

3. Leveraging webpack's DefinePlugin

If you use webpack as your build tool, you can utilize DefinePlugin to define environment variables during compilation. This enables you to directly use these variables in your code to determine whether to execute operations specific to development mode.

javascript
// webpack.config.js
const webpack = require('webpack');

module.exports = {
  plugins: [
    new webpack.DefinePlugin({
      __DEV__: process.env.NODE_ENV !== 'production'
    })
  ]
};

// In Vue component
if (__DEV__) {
  console.log('Currently in development mode');
}

These methods can be selected based on your specific project configuration and requirements. In actual projects, it is generally recommended to manage development and production modes flexibly through environment variables and build tools to ensure the safety and performance of the code in production environments.