Stop struggling with `npm run start` Discover the crucial differences with `npm start` and see code examples

Table of content

  1. Introduction
  2. What is
  3. What is
  4. Key Differences between
  5. Importance of understanding the differences
  6. Code Example 1 – Using
  7. Code Example 2 – Using
  8. Conclusion


If you are a developer, you must have come across the commands 'npm start' and 'npm run start' while working with Node.js. You might have wondered about the difference between these two commands and which one to use in your projects. Let us explore the significant differences between the two and their use cases.

In simple terms, both 'npm start' and 'npm run start' commands are used to start the Node.js application, but there is a subtle difference between them. 'npm start' command is a predefined command that executes the 'start' script defined in the 'package.json' file under the 'scripts' section. On the other hand, 'npm run start' is an explicit command that runs the 'start' script defined in the 'package.json' file.

In essence, 'npm start' is a quicker and easier way to start your Node.js application, whereas 'npm run start' provides more control and customization options. The latter can be useful when dealing with complex applications that require additional configurations for running.

Let us take a closer look at these commands and analyze their differences with the help of some code examples.

What is

Large Language Models (LLMs)?

Large Language Models (LLMs) are advanced artificial intelligence (AI) models that use machine learning and natural language processing (NLP) to generate human-like text. These models are designed to understand the nuances of language and produce coherent, contextually-relevant responses to user queries. LLMs have been used in a variety of applications, including language translation, content generation, and chatbots.

One of the most well-known LLMs is OpenAI's GPT-3 (Generative Pretrained Transformer 3). This model can generate text in a variety of styles and formats, including articles, essays, stories, and even computer code. GPT-3 is notable for its size – it contains 175 billion parameters, making it one of the largest machine learning models ever created. This size allows GPT-3 to generate complex and nuanced responses to user inputs, often surpassing the capabilities of human writers.

Despite its advanced capabilities, GPT-3 is not without its limitations. The model can produce biased or inaccurate results based on the quality of its training data, and it may struggle with complex or abstract concepts. However, improvements in LLM technology suggest that these limitations may be overcome in future iterations, such as the highly-anticipated GPT-4 model.

Key Differences between

When it comes to running a Node.js application, there are two main commands that developers often encounter – npm start and npm run start. While these commands may seem similar at first glance, there are some crucial differences that developers should be aware of.

The primary difference between npm start and npm run start lies in the way they handle scripts defined in the package.json file. npm start looks for a start script in the file and runs it, while npm run start requires the script to be specified explicitly. This means that npm start is more convenient for developers who want to quickly start their application without having to remember the exact script name.

Another key difference is that npm start automatically passes command-line arguments to the script, while npm run start does not. This makes npm start particularly useful for handling environment variables, which can be passed via the command-line arguments.

In terms of best practices, it is generally recommended to use npm start over npm run start when possible. This is because it is simpler and more concise, and makes it easier for developers to quickly run their applications with minimal configuration.

Overall, while the differences between npm start and npm run start may seem minor, they can have a significant impact on the way developers work with Node.js applications. By understanding these differences, developers can optimize their workflow and save time and effort in the long run.

Importance of understanding the differences

Understanding the differences between 'npm run start' and 'npm start' is of utmost importance for developers. While both commands are used to start an application, they perform different functions. 'npm run start' runs a script specified in the 'package.json' file, which can be customized by the developer. On the other hand, 'npm start' runs the pre-defined script named 'start' in the 'package.json' file.

The importance of understanding these differences lies in the fact that it can help developers avoid confusion and reduce errors while running applications. Using 'npm start' is easier and less prone to errors as it follows a standard convention. Moreover, it can save developers considerable time, as they do not need to create or modify a custom script every time they start an application.

Another crucial advantage of understanding the differences is that it can enhance the scalability of applications. By using 'npm start', developers can create applications that can be run without any additional configuration or setup. This makes it easier to deploy and scale applications rapidly, without worrying about compatibility issues or other errors.

In conclusion, developers must understand the differences between 'npm run start' and 'npm start' to streamline their workflow and improve their productivity. It is an essential aspect of developing applications that are efficient, scalable, and easy to maintain. By using the appropriate command, developers can avoid potential errors, save valuable time, and create applications that are more reliable and efficient.

Code Example 1 – Using


Let's say you have a project directory called "my-app" that contains an index.js file. You want to start your project using "npm start". Here's what you would do:

  1. Open your terminal and navigate to the "my-app" directory.

  2. In the terminal, type "npm start" and press enter.

  3. NPM will look for a "start" script in your package.json file.

  4. If it finds it, NPM will execute the script and your project will start.

That's all there is to it! You don't need to type "npm run start" because "npm start" automatically looks for a "start" script in your package.json file. This makes starting your project much simpler and more convenient.

To create a "start" script, simply add the following code to your package.json file:

"scripts": {
  "start": "node index.js"

This script tells NPM to start your project using the "node index.js" command. You can replace "index.js" with the filename of your main script or entry point.

Overall, using "npm start" instead of "npm run start" provides a simpler and more efficient way to start your Node.js project. It also helps you avoid potential errors and confusion when running npm scripts.

Code Example 2 – Using

Using npm start instead of npm run start is the recommended and more concise approach in modern Node.js projects. This is because the start script is one of several built-in scripts that are executed by default when running npm start. These scripts are defined in the package.json file and can include tasks like linting, testing, and building a project.

To use the start script, simply add the following line to your package.json file:

"scripts": {
    "start": "node index.js"

In this example, the start script will run the index.js file when executed with npm start. This can be useful for starting a server or running a development environment.

One key advantage of using npm start is that it comes with automatic restarting of the script in case of any changes made in the project. This is because the nodemon package is included along with the npm start command. Nodemon is a tool that helps developers automatically restart their applications when a file changes.

Additionally, another benefit of using npm start is that it allows developers to define additional scripts to run alongside it. For instance, you can add a script like "heroku-postbuild": "npm run build" to your package.json file so that it runs after deploying to Heroku.

In conclusion, by using npm start instead of npm run start, developers can simplify the process of starting a server or running a development environment. The built-in scripts and support for additional scripts make npm start a more efficient and flexible option for running Node.js projects.


In , understanding the difference between 'npm start' and 'npm run start' can save developers a lot of time and effort when building their applications. 'npm start' is a simpler command that can be used for most projects that do not require any extra configuration. On the other hand, 'npm run start' allows for more customization and can be used to invoke specific scripts defined in the package.json file.

By choosing the right command for the project needs, developers can streamline their development process and avoid unnecessary struggles running commands that may not be necessary or applicable. Additionally, using effective tools like LLMs such as GPT-4 can greatly enhance developers' efficiency by generating high-quality code automatically, reducing the amount of manual work required.

Overall, staying up-to-date on the latest tools and techniques can help developers to be more productive, efficient and effective in building applications that meet the needs of their users. By utilizing tools such as 'npm start' and LLMs like GPT-4, developers can spend more time on the high-level tasks that require their expertise and creativity, rather than getting bogged down in the details.

Cloud Computing and DevOps Engineering have always been my driving passions, energizing me with enthusiasm and a desire to stay at the forefront of technological innovation. I take great pleasure in innovating and devising workarounds for complex problems. Drawing on over 8 years of professional experience in the IT industry, with a focus on Cloud Computing and DevOps Engineering, I have a track record of success in designing and implementing complex infrastructure projects from diverse perspectives, and devising strategies that have significantly increased revenue. I am currently seeking a challenging position where I can leverage my competencies in a professional manner that maximizes productivity and exceeds expectations.
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