Use the expression editor to assist in input and modifying MapboxGL expressions. Live demo version
The easiest way to see the editor in action is to paste an expression into the textarea. Try this one:
[
"match",
[
"get",
"primary_use"
],
"residential",
"#8BC34A",
"commercial",
"#1976D2",
"industrial",
"#FFEB3B",
"mixed use",
"#009688",
"planned district",
"#009688",
"open space",
"#E0F2F1",
"#EEEEEE"
]
Check out the documentation for MapboxGL expressions here.