Table of Contents
pixl-json-util is a simple command-line utility for manipulating JSON files. It allows you to get, add, replace or delete any value anywhere in the JSON file, and save it back to disk. You can traverse nested objects and arrays with dot or slash notation, to target a specific property deep in the tree.
Use npm to install the module:
sudo npm install -g pixl-json-utilThis should add a jsu command to your PATH, which you can use thusly:
jsu FILE COMMAND [PATH] [VALUE] [--ARGS]FILE is the JSON file to load/save, COMMAND is the command to run (see below), PATH is the key name or path (dot notation or slash notation), and VALUE is the new value, if you are adding or replacing. --ARGS are optional, and described below. Example:
jsu package.json set dependencies/async "2.6.0"This would write an async key into the dependencies object, and set the value to 2.6.0 as a string:
"dependencies": {
"async": "2.6.0"
},You can also use dot notation for accessing nested keys, like this:
jsu package.json set dependencies.async "2.6.0"The data type of the value is inferred by the previous value, or if adding a new key it is guessed from the format of the new value. You can, however, force the new type using the --type argument (see Arguments below).
If one of your keys actually contains a dot or a slash, you need to escape it by preceding it with a backslash (\). Beware of shell escaping rules here -- if you quote your value, you only need a single backslash, but if your value is not quoted, you will need a double-backslash to properly escape.
Here are the available commands, and how to use them:
The set command will add or replace a key, and doesn't care if it exists or not. It will also automatically create any parent objects if necessary. Example:
jsu package.json set dependencies/async "2.6.0"The add command will add a new key, and will fail if the key already exists. It will also automatically create any parent objects if necessary. Example:
jsu package.json add scripts/test "mocha test.js"The data type of the new value is guessed by the format. Meaning, if it appears to be a number, it will be written as such (without quotes), or else it will be written as a string. To customize this, and to support adding booleans, see the --type argument below.
The replace command will replace an existing key with a new value, and fail if the key or any parent objects don't exist. Example:
jsu package.json replace repository/type "git"The delete command will delete an existing key, and fail if the key or any parent objects don't exist. Example:
jsu package.json delete bugs/urlThe get command simply fetches an existing value, and outputs it to the console. It does not save over the file. Example:
jsu package.json get versionIf you target an object instead of a plain value, the object and all its contents are pretty-printed and outputted:
jsu package.json get repositoryExample output:
{
"type": "git",
"url": "https://github.com/jhuckaby/pixl-json-util"
}The validate command simply validates the syntax of the JSON file, and exits without saving. The exit code will be 0 upon success (valid), or non-zero if an error occurred parsing the file. Details will be available in the STDERR output. Example:
jsu package.json validateThe echo command simply echoes the entire file to the console, without saving any changes. This command is also the default action if no command is specified. This can be used to quickly pretty-print a compact JSON file. Example:
jsu some_compact_file.jsonThe pretty command will pretty-print the file, and save it back to disk, replacing the original file. Example:
jsu some_compact_file.json prettyHere are the optional arguments you can specify. Each argument name should be preceded with a double-dash (--).
The --type argument allows you to specify the exact data format of the new value. By default this is inferred by the existing property value, or by examining the syntax of the new value on the CLI. Accepted types are:
| Type | Description |
|---|---|
string |
Wrapped in quotes, e.g. "MIT". |
number |
Integer or float, written without quotes, e.g. 45.0. |
boolean |
Written as true or false without quotes, can also specify as 1 or 0 on the CLI. |
object |
Used for adding complex JSON fragments. See Adding Complex JSON below. |
null |
Writes out a literal null as the value. |
Example use:
jsu user.json add status/enabled false --type booleanThis would add a new property in the status object called enabled, set to boolean false:
"status": {
"enabled": false
}Note that specifying the data type should only be required in special situations, like when you are forcefully changing the type of an existing property, or adding a new one and a guess of the syntax would be incorrect. The syntax of new property values is guessed to be a number or a string, but never a boolean, object or null.
By default all JSON files are saved back out to disk using pretty-printing, and a single tab (\t) character as the indent. To change this, you can add a --indent argument, followed by any number of spaces or tabs you want. Example (2 spaces):
jsu package.json set version "2.0.0" --indent " "If you would prefer your JSON file be compacted and printed onto one line, add the --compact argument. Example:
jsu package.json set license "MIT" --compactThe --atomic argument causes the file save operation to be "atomic". Meaning, the JSON is first written to a temporary file in the same directory, then renamed over the original file. The temporary file is named by appending the current PID, followed by a .tmp file extension. Example:
jsu package.json set name "pixl-json-util" --atomicThe --quiet argument silences all output from the script, unless an error occurs. Example:
jsu package.json add devDependencies/mocha "5.2.0" --quietThe --dryrun argument doesn't actually save any changes to disk, and instead simply outputs the final JSON file to the console. This is great for examining a change before you make it on the real file. Example:
jsu package.json delete devDependencies --dryrunThe --help argument prints out this README to the console and exits, without taking any other action. Example:
jsu --helpYou can actually add entire JSON fragments to your file. Just make sure you are replacing an existing object, or you specify --type object so the engine knows to parse your value as JSON when applying to the document. Example:
jsu package.json set dependencies "{\"pixl-cli\":\"^1.0.0\"}" --type objectMake sure you properly escape your quotes, when attempting this.
You can traverse arrays just like any other object, simply by specifying the array index as the key. Example:
jsu package.json set keywords/1 "utility"The MIT License (MIT)
Copyright (c) 2018 - 2024 Joseph Huckaby.
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