Implement split/join

CHANGELOG.md

@@ -3,6 +3,7 @@
 ### ✨ Features and improvements
 - Add `setiClusterOptions` to update cluster properties of the added sources: fixing these issues ([#429](https://github.com/maplibre/maplibre-gl-js/issues/429)) and ([1384](https://github.com/maplibre/maplibre-gl-js/issues/1384))
 - Add types for `workerOptions` and `_options` in `geojson_source.ts`
+- Add `split` and `join` expressions ([#2064](https://github.com/maplibre/maplibre-gl-js/pull/2064))
 - *...Add new stuff here...*
 ### 🐞 Bug fixes
 - *...Add new stuff here...*

build/generate-style-spec.ts

@@ -211,7 +211,9 @@ export type ExpressionSpecification =
     | ['concat', ...(ExpressionInputType | ExpressionSpecification)[]] // at least two inputs required -> string
     | ['downcase', string | ExpressionSpecification] // string
     | ['is-supported-script', string | ExpressionSpecification] // boolean
+    | ['join', string, (string | ExpressionSpecification)[]] // string
     | ['resolved-locale', CollatorExpressionSpecification] // string
+    | ['split', string, string | ExpressionSpecification] // string[]
     | ['upcase', string | ExpressionSpecification] // string
     // Color
     | ['rgb', number | ExpressionSpecification, number | ExpressionSpecification, number | ExpressionSpecification] // color

src/style-spec/expression/definitions/index.ts

@@ -554,6 +554,16 @@ CompoundExpression.register(expressions, {
         varargs(ValueType),
         (ctx, args) => args.map(arg => valueToString(arg.evaluate(ctx))).join('')
     ],
+    'split': [
+        array(StringType),
+        [StringType, StringType],
+        (ctx, [delim, s]) => s.evaluate(ctx).split(delim.evaluate(ctx))
+    ],
+    'join': [
+        StringType,
+        [StringType, array(StringType)],
+        (ctx, [delim, arr]) => arr.evaluate(ctx).join(delim.evaluate(ctx))
+    ],
     'resolved-locale': [
         StringType,
         [CollatorType],

src/style-spec/reference/v8.json

@@ -3711,6 +3711,24 @@
             "macos": "0.9.0"
           }
         }
+      },
+      "split": {
+        "doc": "Returns an array of strings split by the specified delimiter string",
+        "group": "String",
+        "sdk-support": {
+          "basic functionality": {
+            "js": "3.0.0"
+          }
+        }
+      },
+      "join": {
+        "doc": "Returns a string formed from joining the elements of an array with a specified delimiter in between",
+        "group": "String",
+        "sdk-support": {
+          "basic functionality": {
+            "js": "3.0.0"
+          }
+        }
       }
     }
   },

test/integration/expression/tests/join/basic/test.json

@@ -0,0 +1,13 @@
+{
+  "expression": ["join", ";", ["literal", ["a", "b", "c"]]],
+  "inputs": [[{}, {}]],
+  "expected": {
+    "compiled": {
+      "result": "success",
+      "isFeatureConstant": true,
+      "isZoomConstant": true,
+      "type": "string"
+    },
+    "outputs": ["a;b;c"]
+  }
+}

test/integration/expression/tests/join/coercion/test.json

@@ -0,0 +1,23 @@
+{
+  "expression": ["join", "/", ["get", "a"]],
+  "inputs": [
+    [{}, {"properties": {"a": ["a", "b", "c"]}}],
+    [{}, {"properties": {"a": ["a", "b"]}}],
+    [{}, {"properties": {"a": ["a"]}}],
+    [{}, {"properties": {"a": [""]}}]
+  ],
+  "expected": {
+    "compiled": {
+      "result": "success",
+      "isFeatureConstant": false,
+      "isZoomConstant": true,
+      "type": "string"
+    },
+    "outputs": [
+      "a/b/c",
+      "a/b",
+      "a",
+      ""
+    ]
+  }
+}

test/integration/expression/tests/split/basic/test.json

@@ -0,0 +1,13 @@
+{
+  "expression": ["split", ";", "a;b;c"],
+  "inputs": [[{}, {}, {}]],
+  "expected": {
+    "compiled": {
+      "result": "success",
+      "isFeatureConstant": true,
+      "isZoomConstant": true,
+      "type": "array<string>"
+    },
+    "outputs": [["a", "b", "c"]]
+  }
+}

test/integration/expression/tests/split/coercion/test.json

@@ -0,0 +1,23 @@
+{
+  "expression": ["split", "/", ["get", "s"]],
+  "inputs": [
+    [{}, {"properties": {"s": "a/b/c"}}],
+    [{}, {"properties": {"s": "a/b"}}],
+    [{}, {"properties": {"s": "a"}}],
+    [{}, {"properties": {"s": ""}}]
+  ],
+  "expected": {
+    "compiled": {
+      "result": "success",
+      "isFeatureConstant": false,
+      "isZoomConstant": true,
+      "type": "array<string>"
+    },
+    "outputs": [
+      ["a", "b", "c"],
+      ["a", "b"],
+      ["a"],
+      [""]
+    ]
+  }
+}