4.4 KiB
JSON
Encode and decode to and from JSON. Note that, unless you have multiple JSON documents in a single file, YAML is a superset of JSON - so yq can read any json file without doing anything special.
If you do have mulitple JSON documents in a single file (e.g. NDJSON) then you will need to explicity use the json parser -p=json.
This means you don't need to 'convert' a JSON file to YAML - however if you want idiomatic YAML styling, then you can use the -P/--prettyPrint flag, see examples below.
{% hint style="warning" %} Note that versions prior to 4.18 require the 'eval/e' command to be specified.
yq e <exp> <file>
{% endhint %}
Parse json: simple
JSON is a subset of yaml, so all you need to do is prettify the output
Given a sample.json file of:
{"cat": "meow"}
then
yq -P '.' sample.json
will output
cat: meow
Parse json: complex
JSON is a subset of yaml, so all you need to do is prettify the output
Given a sample.json file of:
{"a":"Easy! as one two three","b":{"c":2,"d":[3,4]}}
then
yq -P '.' sample.json
will output
a: Easy! as one two three
b:
c: 2
d:
- 3
- 4
Encode json: simple
Given a sample.yml file of:
cat: meow
then
yq -o=json '.' sample.yml
will output
{
"cat": "meow"
}
Encode json: simple - in one line
Given a sample.yml file of:
cat: meow # this is a comment, and it will be dropped.
then
yq -o=json -I=0 '.' sample.yml
will output
{"cat":"meow"}
Encode json: comments
Given a sample.yml file of:
cat: meow # this is a comment, and it will be dropped.
then
yq -o=json '.' sample.yml
will output
{
"cat": "meow"
}
Encode json: anchors
Anchors are dereferenced
Given a sample.yml file of:
cat: &ref meow
anotherCat: *ref
then
yq -o=json '.' sample.yml
will output
{
"cat": "meow",
"anotherCat": "meow"
}
Encode json: multiple results
Each matching node is converted into a json doc. This is best used with 0 indent (json document per line)
Given a sample.yml file of:
things: [{stuff: cool}, {whatever: cat}]
then
yq -o=json -I=0 '.things[]' sample.yml
will output
{"stuff":"cool"}
{"whatever":"cat"}
Roundtrip NDJSON
Unfortunately the json encoder strips leading spaces of values.
Given a sample.json file of:
{"this": "is a multidoc json file"}
{"each": ["line is a valid json document"]}
{"a number": 4}
then
yq -p=json -o=json -I=0 sample.json
will output
{"this":"is a multidoc json file"}
{"each":["line is a valid json document"]}
{"a number":4}
Roundtrip multi-document JSON
The NDJSON parser can also handle multiple multi-line json documents in a single file!
Given a sample.json file of:
{
"this": "is a multidoc json file"
}
{
"it": [
"has",
"consecutive",
"json documents"
]
}
{
"a number": 4
}
then
yq -p=json -o=json -I=2 sample.json
will output
{
"this": "is a multidoc json file"
}
{
"it": [
"has",
"consecutive",
"json documents"
]
}
{
"a number": 4
}
Update a specific document in a multi-document json
Documents are indexed by the documentIndex or di operator.
Given a sample.json file of:
{"this": "is a multidoc json file"}
{"each": ["line is a valid json document"]}
{"a number": 4}
then
yq -p=json -o=json -I=0 '(select(di == 1) | .each ) += "cool"' sample.json
will output
{"this":"is a multidoc json file"}
{"each":["line is a valid json document","cool"]}
{"a number":4}
Find and update a specific document in a multi-document json
Use expressions as you normally would.
Given a sample.json file of:
{"this": "is a multidoc json file"}
{"each": ["line is a valid json document"]}
{"a number": 4}
then
yq -p=json -o=json -I=0 '(select(has("each")) | .each ) += "cool"' sample.json
will output
{"this":"is a multidoc json file"}
{"each":["line is a valid json document","cool"]}
{"a number":4}
Decode NDJSON
Given a sample.json file of:
{"this": "is a multidoc json file"}
{"each": ["line is a valid json document"]}
{"a number": 4}
then
yq -p=json sample.json
will output
this: is a multidoc json file
---
each:
- line is a valid json document
---
a number: 4