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node_modules/@mapbox/mapbox-gl-style-spec/expression/is_constant.js

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+// @flow
+
+import CompoundExpression from './compound_expression.js';
+import Within from './definitions/within.js';
+import type {Expression} from './expression.js';
+
+function isFeatureConstant(e: Expression): boolean {
+    if (e instanceof CompoundExpression) {
+        if (e.name === 'get' && e.args.length === 1) {
+            return false;
+        } else if (e.name === 'feature-state') {
+            return false;
+        } else if (e.name === 'has' && e.args.length === 1) {
+            return false;
+        } else if (
+            e.name === 'properties' ||
+            e.name === 'geometry-type' ||
+            e.name === 'id'
+        ) {
+            return false;
+        } else if (/^filter-/.test(e.name)) {
+            return false;
+        }
+    }
+
+    if (e instanceof Within) {
+        return false;
+    }
+
+    let result = true;
+    e.eachChild(arg => {
+        if (result && !isFeatureConstant(arg)) { result = false; }
+    });
+    return result;
+}
+
+function isStateConstant(e: Expression): boolean {
+    if (e instanceof CompoundExpression) {
+        if (e.name === 'feature-state') {
+            return false;
+        }
+    }
+    let result = true;
+    e.eachChild(arg => {
+        if (result && !isStateConstant(arg)) { result = false; }
+    });
+    return result;
+}
+
+function isGlobalPropertyConstant(e: Expression, properties: Array<string>): boolean {
+    if (e instanceof CompoundExpression && properties.indexOf(e.name) >= 0) { return false; }
+    let result = true;
+    e.eachChild((arg) => {
+        if (result && !isGlobalPropertyConstant(arg, properties)) { result = false; }
+    });
+    return result;
+}
+
+export {isFeatureConstant, isGlobalPropertyConstant, isStateConstant};