planning

node_modules/@mapbox/mapbox-gl-style-spec/migrate/expressions.js

@@ -0,0 +1,39 @@
+// @flow
+
+import {
+    eachLayer,
+    eachProperty
+} from '../visit.js';
+import {isExpression} from '../expression/index.js';
+import convertFunction, {convertTokenString} from '../function/convert.js';
+import convertFilter from '../feature_filter/convert.js';
+
+import type {StyleSpecification} from '../types.js';
+
+/**
+ * Migrate the given style object in place to use expressions. Specifically,
+ * this will convert (a) "stop" functions, and (b) legacy filters to their
+ * expression equivalents.
+ */
+export default function(style: StyleSpecification): StyleSpecification {
+    const converted = [];
+
+    eachLayer(style, (layer) => {
+        if (layer.filter) {
+            layer.filter = (convertFilter(layer.filter): any);
+        }
+    });
+
+    eachProperty(style, {paint: true, layout: true}, ({path, value, reference, set}) => {
+        if (isExpression(value)) return;
+        if (typeof value === 'object' && !Array.isArray(value)) {
+            set(convertFunction(value, reference));
+            converted.push(path.join('.'));
+        } else if (reference.tokens && typeof value === 'string') {
+            set(convertTokenString(value));
+        }
+    });
+
+    return style;
+}
+