Getting Started

Getting Started

The yajs module can be used either as a command-line tool or as a standard js library.

Both modes will require node.js to be to be installed. The minimum tested version is 6.0, so any version above this should work.

Command-line

To install it as a command-line:

npm install -g yajson-stream

Then test it with:

$ echo '{ "hello": "world" }' | yajs '$.hello'
"world"

Library

To install it as a library:

npm install --save yajson-stream

Then it can be used as regular node stream:

const yajs = require('yajson-stream');
const { createReadStream } = require('fs');

createReadStream('./package.json').
    pipe(yajs('$.author')).
    on('data', data => {
        console.log(data.path); // outputs [ 'author' ]
        console.log(data.value); // outputs 'Thiago Souza <thiago@elastic.co>'
    });

First selections

Let's take this project's package.json as an example. Here are a few basic selections that exemplifies what can be done:

• $.dependencies - Get dependencies object

$ curl -s https://raw.githubusercontent.com/tsouza/yajs/master/package.json | yajs '$.dependencies'
{"@types/jsonpath":"^0.2.0","@types/lodash":"^4.14.92","@types/node":"^9.3.0","@types/through":"0.0.29","antlr4":"^4.7.1","antlr4ts":"^0.4.1-alpha.0","lodash":"^4.17.4","through":"^2.3.8"}

• $.dependencies.* - Get all dependencies versions

$ curl -s https://raw.githubusercontent.com/tsouza/yajs/master/package.json | yajs '$.dependencies.*'
"^0.2.0"
"^4.14.92"
"^9.3.0"
"0.0.29"
"^4.7.1"
"^0.4.1-alpha.0"
"^4.17.4"
"^2.3.8"