Remove duplicates in JSON to CSV values using jq - syntax

Question

Here I'm trying to convert json to csv. Also, I'm trying to ignore duplicate values of 'color' attribute in same command. I have tried with below jq cmd and getting bash: syntax error near unexpected token `(' error. Please help me to resolve this error.
jq -r '["color","category","type"], ([].colors | 'unique_by(.color)' | [.color, .category, .type]) | #csv' test.json > test.csv
My JSON file:
{
"colors": [
{
"color": "black",
"category": "hue",
"type": "primary",
"code": {
"rgba": [255,255,255,1],
"hex": "#000"
}
},
{
"color": "white",
"category": "value",
"code": {
"rgba": [0,0,0,1],
"hex": "#FFF"
}
},
{
"color": "red",
"category": "hue",
"type": "primary",
"code": {
"rgba": [255,0,0,1],
"hex": "#FF0"
}
},
{
"color": "black",
"category": "hue",
"type": "primary",
"code": {
"rgba": [0,0,255,1],
"hex": "#00F"
}
},
{
"color": "yellow",
"category": "hue",
"type": "primary",
"code": {
"rgba": [255,255,0,1],
"hex": "#FF0"
}
},
{
"color": "white",
"category": "hue",
"type": "secondary",
"code": {
"rgba": [0,255,0,1],
"hex": "#0F0"
}
}
]
}

Answer 1

Are you looking for this?
jq -r '.colors | unique_by(.color)[] | [.color, .category, .type] | #csv'
"black","hue","primary"
"red","hue","primary"
"white","value",
"yellow","hue","primary"
Demo
To add a default value (and make every line have the same amount of values), add // "<default_value>" when creating the final array. For instance, with "" as default, it'd be:
jq -r '.colors | unique_by(.color)[] | [.color//"", .category//"", .type//""] | #csv'
"black","hue","primary"
"red","hue","primary"
"white","value",""
"yellow","hue","primary"
Demo