jsonmap
streaming command line newline-delimited json transformer utility
you must pipe newline-delimited JSON data in (one JSON stringified object per line). you will receive the same format out
installation
$ npm install jsonmap -g
usage
this
will be each line of JSON that gets parsed out of the incoming newline-delimited json stream. you can also use _
as a shorthand for this
, and you are allowed to require
things.
there are two 'modes', the first is where you modify this
:
$ echo '{"foo": "bar"}\n{"baz": "taco"}' | jsonmap "this.pizza = 1"{"foo":"bar","pizza":1}{"baz":"taco","pizza":1}
the second mode is where you return a new object:
$ echo '{"foo": "bar", "cat": "yes"}\n{"baz": "taco", "cat": "yes"}' | jsonmap "{cat: this.cat}"{"cat":"yes"}{"cat":"yes"}
if your code gets too complex and you'd rather use an external file you can also just specify a module to get required:
$ echo '{"foo": "bar"}\n{"baz": "taco"}' | jsonmap --file=transform.js{"foo":"bar","pizza":1}{"baz":"taco","pizza":1}
the above will work if transform.js
has the following contents:
module { thispizza = 1}
if you have es6 template strings enabled on your platform (e.g. iojs), template strings will work as well
$ echo '{"meal": "pizza"}\n{"meal": "taco"}' | jsonmap '`i love ${this.meal}`'"i love pizza""i love taco"
if you want to provide a through2 function in a file for more control, or async, you can
$ echo '{"foo": "bar"}\n{"baz": "taco"}' | jsonmap --file=transform.js --through{"foo":"bar","pizza":1}{"baz":"taco","pizza":1}
the above will work if transform.js
has the following contents:
module { var self = this; ifobjfoo === 'bar' return // skip the bar process}
you disable JSON parsing (to e.g. process a file line by line as JS strings) by passing jsonmap --no-parse