Enable implicit type assertions for array types

src/style-spec/expression/parsing_context.js

@@ -4,6 +4,9 @@ const Scope = require('./scope');
 const {checkSubtype} = require('./types');
 const ParsingError = require('./parsing_error');
 const Literal = require('./definitions/literal');
+const Assertion = require('./definitions/assertion');
+const ArrayAssertion = require('./definitions/array');
+const Coercion = require('./definitions/coercion');
 
 import type {Expression} from './expression';
 import type {Type} from './types';
@@ -77,10 +80,10 @@ class ParsingContext {
                         expected.kind === 'boolean';
 
                     if (canAssert && actual.kind === 'value') {
-                        const Assertion = require('./definitions/assertion');
                         parsed = new Assertion(expected, [parsed]);
+                    } else if (expected.kind === 'array' && actual.kind === 'value') {
+                        parsed = new ArrayAssertion(expected, parsed);
                     } else if (expected.kind === 'color' && (actual.kind === 'value' || actual.kind === 'string')) {
-                        const Coercion = require('./definitions/coercion');
                         parsed = new Coercion(expected, [parsed]);
                     }
 

test/integration/expression-tests/array/implicit-1/test.json

@@ -0,0 +1,21 @@
+{
+  "expression": ["at", 0, ["get", "array"]],
+  "inputs": [
+    [{}, {"properties": {"array": [0, 1, 2]}}],
+    [{}, {"properties": {"array": "not"}}]
+  ],
+  "expected": {
+    "compiled": {
+      "result": "success",
+      "isFeatureConstant": false,
+      "isZoomConstant": true,
+      "type": "value"
+    },
+    "outputs": [
+      0,
+      {
+        "error": "Expected value to be of type array, but found string instead."
+      }
+    ]
+  }
+}

test/integration/expression-tests/array/implicit-2/test.json

@@ -0,0 +1,26 @@
+{
+  "propertySpec": {"type": "array", "value": "string"},
+  "expression": ["get", "array"],
+  "inputs": [
+    [{}, {"properties": {"array": ["a", "b"]}}],
+    [{}, {"properties": {"array": [1, 2]}}],
+    [{}, {"properties": {"array": "not"}}]
+  ],
+  "expected": {
+    "compiled": {
+      "result": "success",
+      "isFeatureConstant": false,
+      "isZoomConstant": true,
+      "type": "array<string>"
+    },
+    "outputs": [
+      ["a", "b"],
+      {
+        "error": "Expected value to be of type array<string>, but found array<number, 2> instead."
+      },
+      {
+        "error": "Expected value to be of type array<string>, but found string instead."
+      }
+    ]
+  }
+}

test/integration/expression-tests/array/implicit-3/test.json

@@ -0,0 +1,26 @@
+{
+  "propertySpec": {"type": "array", "value": "number", "length": 2},
+  "expression": ["get", "array"],
+  "inputs": [
+    [{}, {"properties": {"array": [1, 2]}}],
+    [{}, {"properties": {"array": [1, 2, 3]}}],
+    [{}, {"properties": {"array": "not"}}]
+  ],
+  "expected": {
+    "compiled": {
+      "result": "success",
+      "isFeatureConstant": false,
+      "isZoomConstant": true,
+      "type": "array<number, 2>"
+    },
+    "outputs": [
+      [1, 2],
+      {
+        "error": "Expected value to be of type array<number, 2>, but found array<number, 3> instead."
+      },
+      {
+        "error": "Expected value to be of type array<number, 2>, but found string instead."
+      }
+    ]
+  }
+}