How to Use the Command 'json5' (with examples)

JSON5 is a cool utility designed to convert JSON5 files into JSON format. JSON5 is an extension of JSON that allows for more human-friendly features like comments, unquoted keys, and trailing commas. The json5 command-line tool helps simplify the conversion process, ensuring that your JSON5 files become standard JSON compliant with minimal hassle. This article will delve into various use cases for the json5 command, providing clear examples and explanations for each one.

Use case 1: Convert JSON5 stdin to JSON stdout

Code:

echo input | json5

Motivation:

This command is extremely useful when you have JSON5 content being piped from another process or command, and you need to quickly convert it into JSON format on-the-fly. It allows for seamless integration in scripts where JSON5 data needs to be processed as JSON without creating intermediate files.

Explanation:

• echo input: Simulates a command that outputs JSON5 data to stdout.
• |: Pipes the output of the echo input command into another command.
• json5: The main command that processes the incoming JSON5 input and converts it to JSON format.

Example output:

If the piped input is a JSON5 string like {"key": "value", trailingCommaAllowed: true,} the output would be the JSON equivalent:

{"key": "value", "trailingCommaAllowed": true}

Use case 2: Convert a JSON5 file to JSON and output to stdout

Code:

json5 path/to/input_file.json5

Motivation:

This approach is perfect when you want to quickly see the JSON output of an existing JSON5 file. It is incredibly handy for debugging or verifying the contents of a JSON5 file without altering the source file itself.

Explanation:

• json5: The main command to convert JSON5 to JSON.
• path/to/input_file.json5: The path to the input file containing JSON5 data. json5 will read this file, process its contents, and output valid JSON to the standard output.

Example output:

Assuming input_file.json5 contains JSON5 like:

{
  // A comment
  key: "value", // Trailing comma
}

The output will be:

{
  "key": "value"
}

Use case 3: Convert a JSON5 file to the specified JSON file

Code:

json5 path/to/input_file.json5 --out-file path/to/output_file.json

Motivation:

When there’s a need to persist the conversion result, this option is ideal as it specifies the exact file where the converted JSON should be saved. This is particularly beneficial for automated processes that require the JSON data to be available in a separate file for further use or sharing.

Explanation:

• json5: Initiates the conversion process.
• path/to/input_file.json5: Specifies the JSON5 source file.
• --out-file: Signals to the command that the output should be saved to a file rather than printed to the terminal.
• path/to/output_file.json: The destination path where the JSON output will be written.

Example output:

If input_file.json5 contains:

{unquoted: "keys"}

output_file.json will contain:

{"unquoted": "keys"}

Use case 4: Validate a JSON5 file

Code:

json5 path/to/input_file.json5 --validate

Motivation:

Validation is an essential step when working with files, especially if you are incorporating JSON5 data from an external source. By validating a JSON5 file, you ensure the file not only syntactically adheres to JSON5 rules but is also semantically valid before processing it further.

Explanation:

• json5: The command to use.
• path/to/input_file.json5: The target JSON5 file whose validity needs checking.
• --validate: A flag that instructs the json5 command to perform validation on the input file.

Example output:

For a valid file, there may be no output, signifying it passed validation. If invalid, you might see an error like:

Error: Unexpected token in JSON5 at position 20

Use case 5: Specify the number of spaces to indent by (or “t” for tabs)

Code:

json5 --space 4 path/to/input_file.json5

Motivation:

When readability of the JSON output is a priority, specifying indentation can greatly enhance the clarity of the structured data. This is practical for developers and others who often inspect and edit JSON files manually.

Explanation:

• json5: The primary command.
• --space 4: This option specifies that the output JSON should be indented using 4 spaces per level, making it human-readable.
• path/to/input_file.json5: The input file in JSON5 format that needs conversion.

Example output:

Given an unformatted JSON5 input, the output will exhibit clear indentation such as:

{
    "someKey": "someValue",
    "nestedObject": {
        "anotherKey": "anotherValue"
    }
}

Use case 6: Display help

Code:

json5 --help

Motivation:

Understanding a command’s features is fundamental to leveraging its full capabilities. The help option is an invaluable resource that provides quick insights into available options and usage patterns directly from the command line.

Explanation:

• json5: The command.
• --help: A flag that signals the command to display helpful documentation about all the available command line options, syntax, and examples.

Example output:

The –help command typically outputs a list of command-line options:

Usage: json5 [input_file] [options]

Options:
  --version      Show version number                                   [boolean]
  --space, -s    Number of spaces to indent the output                   [number]
  --validate     Validate input JSON5                                          
  --out-file, -o Write output to file                                       
  --help         Show help                                          [boolean]

Conclusion:

The json5 command-line tool is a versatile utility for managing and converting JSON5 files. Whether you need to perform simple validation, convert JSON5 to standard JSON, format JSON outputs neatly, or explore usage options, json5 undoubtedly offers comprehensive solutions for developers and data enthusiasts alike. With these examples, anyone should be able to efficiently incorporate JSON5 into their workflows, harnessing the benefits of JSON5 while ensuring compatibility with standard JSON.