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node_modules/jsx-ast-utils/src/getPropValue.js

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+import getValue, { getLiteralValue } from './values';
+
+const extractValue = (attribute, extractor) => {
+  if (attribute && attribute.type === 'JSXAttribute') {
+    if (attribute.value === null) {
+      // Null valued attributes imply truthiness.
+      // For example: <div aria-hidden />
+      // See: https://facebook.github.io/react/docs/jsx-in-depth.html#boolean-attributes
+      return true;
+    }
+
+    return extractor(attribute.value);
+  }
+
+  return undefined;
+};
+
+/**
+ * Returns the value of a given attribute.
+ * Different types of attributes have their associated
+ * values in different properties on the object.
+ *
+ * This function should return the most *closely* associated
+ * value with the intention of the JSX.
+ *
+ * @param attribute - The JSXAttribute collected by AST parser.
+ */
+export default function getPropValue(attribute) {
+  return extractValue(attribute, getValue);
+}
+
+/**
+ * Returns the value of a given attribute.
+ * Different types of attributes have their associated
+ * values in different properties on the object.
+ *
+ * This function should return a value only if we can extract
+ * a literal value from its attribute (i.e. values that have generic
+ * types in JavaScript - strings, numbers, booleans, etc.)
+ *
+ * @param attribute - The JSXAttribute collected by AST parser.
+ */
+export function getLiteralPropValue(attribute) {
+  return extractValue(attribute, getLiteralValue);
+}