jsonfilter

jsonfilter

Streaming JSON filtering on the command line. Supports JSON querying and expression based filtering.

Works great for JSON datasets that are too big to JSON.parse() or for situations where you want to start reading data immediately.

Powered by JSONStream which is powered by jsonparse

usage

Pipe JSON data to stdin!

jsonfilter <selector> [--match="filter expression"]

filter is a string to 'query' your JSON with.

Matches will be printed as Newline Delimited JSON (NDJSON)

some examples:

Emit the value of a particular key by naming it, e.g. "name" matches the key name in an object and returns the value:

$ echo '{"name": "Joe Blogs", "age": 28}' | jsonfilter "name"
"Joe Blogs"

rows.* matches any child elements of rows, e.g.:

$ echo '{"name": "foo", "type": "bar"}{"name": "foobar", "type": "barfoo"}' | jsonfilter "name"
"foo"
"foobar"

"rows.*" matches any child elements (items inside the array) of rows, e.g.:

$ echo '{"rows": [ {"this object": "will be matched"}, {"so will": "this one"} ]}' | jsonfilter "rows.*"
{"this object": "will be matched"}
{"so will": "this one"}

"rows.*.doc" matches all children of rows with key doc, e.g.:

$ echo '{"rows": [ {"doc": {"this object": "will be matched"}, "foo": "bar"} ]}' | jsonfilter "rows.*.doc"
{'this object': 'will be matched'}

"rows..doc" recursively matches all children of rows and emits all with key doc, e.g.:

$ echo '{"rows": [ {"foo": {"bar": {"baz": {"taco": {"doc": "woo"}}}}} ]}' | jsonfilter "rows..doc"
"woo"

matching

by default all matched objects are emitted. You can supply a custom JS expression to filter out matching objects with the --match option.

$ echo '{"name": "foo", "type": "bar"}{"name": "foobar", "type": "barfoo"}' | jsonfilter "name" --match="this === 'foo'"
# foo

$ echo '{"name": "foo", "type": "bar"}{"name": "foobar", "type": "barfoo"}' | jsonfilter --match="this.name === 'foo'"
{"name": "foo", "type": "bar"}

$ echo '{"name": "foo", "type": "bar"}{"name": "foobar", "type": "barfoo"}' | jsonfilter --match="this.name.indexOf('foo') > -1"
{"name": "foo", "type": "bar"}
{"name": "foobar", "type": "barfoo"}