react app

react-app/node_modules/react/lib/traverseAllChildren.js

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+/**
+ * Copyright 2013-2015, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ * @providesModule traverseAllChildren
+ */
+
+'use strict';
+
+var ReactElement = require("./ReactElement");
+var ReactFragment = require("./ReactFragment");
+var ReactInstanceHandles = require("./ReactInstanceHandles");
+
+var getIteratorFn = require("./getIteratorFn");
+var invariant = require("./invariant");
+var warning = require("./warning");
+
+var SEPARATOR = ReactInstanceHandles.SEPARATOR;
+var SUBSEPARATOR = ':';
+
+/**
+ * TODO: Test that a single child and an array with one item have the same key
+ * pattern.
+ */
+
+var userProvidedKeyEscaperLookup = {
+  '=': '=0',
+  '.': '=1',
+  ':': '=2'
+};
+
+var userProvidedKeyEscapeRegex = /[=.:]/g;
+
+var didWarnAboutMaps = false;
+
+function userProvidedKeyEscaper(match) {
+  return userProvidedKeyEscaperLookup[match];
+}
+
+/**
+ * Generate a key string that identifies a component within a set.
+ *
+ * @param {*} component A component that could contain a manual key.
+ * @param {number} index Index that is used if a manual key is not provided.
+ * @return {string}
+ */
+function getComponentKey(component, index) {
+  if (component && component.key != null) {
+    // Explicit key
+    return wrapUserProvidedKey(component.key);
+  }
+  // Implicit key determined by the index in the set
+  return index.toString(36);
+}
+
+/**
+ * Escape a component key so that it is safe to use in a reactid.
+ *
+ * @param {*} key Component key to be escaped.
+ * @return {string} An escaped string.
+ */
+function escapeUserProvidedKey(text) {
+  return ('' + text).replace(
+    userProvidedKeyEscapeRegex,
+    userProvidedKeyEscaper
+  );
+}
+
+/**
+ * Wrap a `key` value explicitly provided by the user to distinguish it from
+ * implicitly-generated keys generated by a component's index in its parent.
+ *
+ * @param {string} key Value of a user-provided `key` attribute
+ * @return {string}
+ */
+function wrapUserProvidedKey(key) {
+  return '$' + escapeUserProvidedKey(key);
+}
+
+/**
+ * @param {?*} children Children tree container.
+ * @param {!string} nameSoFar Name of the key path so far.
+ * @param {!number} indexSoFar Number of children encountered until this point.
+ * @param {!function} callback Callback to invoke with each child found.
+ * @param {?*} traverseContext Used to pass information throughout the traversal
+ * process.
+ * @return {!number} The number of children in this subtree.
+ */
+function traverseAllChildrenImpl(
+  children,
+  nameSoFar,
+  indexSoFar,
+  callback,
+  traverseContext
+) {
+  var type = typeof children;
+
+  if (type === 'undefined' || type === 'boolean') {
+    // All of the above are perceived as null.
+    children = null;
+  }
+
+  if (children === null ||
+      type === 'string' ||
+      type === 'number' ||
+      ReactElement.isValidElement(children)) {
+    callback(
+      traverseContext,
+      children,
+      // If it's the only child, treat the name as if it was wrapped in an array
+      // so that it's consistent if the number of children grows.
+      nameSoFar === '' ? SEPARATOR + getComponentKey(children, 0) : nameSoFar,
+      indexSoFar
+    );
+    return 1;
+  }
+
+  var child, nextName, nextIndex;
+  var subtreeCount = 0; // Count of children found in the current subtree.
+
+  if (Array.isArray(children)) {
+    for (var i = 0; i < children.length; i++) {
+      child = children[i];
+      nextName = (
+        (nameSoFar !== '' ? nameSoFar + SUBSEPARATOR : SEPARATOR) +
+        getComponentKey(child, i)
+      );
+      nextIndex = indexSoFar + subtreeCount;
+      subtreeCount += traverseAllChildrenImpl(
+        child,
+        nextName,
+        nextIndex,
+        callback,
+        traverseContext
+      );
+    }
+  } else {
+    var iteratorFn = getIteratorFn(children);
+    if (iteratorFn) {
+      var iterator = iteratorFn.call(children);
+      var step;
+      if (iteratorFn !== children.entries) {
+        var ii = 0;
+        while (!(step = iterator.next()).done) {
+          child = step.value;
+          nextName = (
+            (nameSoFar !== '' ? nameSoFar + SUBSEPARATOR : SEPARATOR) +
+            getComponentKey(child, ii++)
+          );
+          nextIndex = indexSoFar + subtreeCount;
+          subtreeCount += traverseAllChildrenImpl(
+            child,
+            nextName,
+            nextIndex,
+            callback,
+            traverseContext
+          );
+        }
+      } else {
+        if ("production" !== process.env.NODE_ENV) {
+          ("production" !== process.env.NODE_ENV ? warning(
+            didWarnAboutMaps,
+            'Using Maps as children is not yet fully supported. It is an ' +
+            'experimental feature that might be removed. Convert it to a ' +
+            'sequence / iterable of keyed ReactElements instead.'
+          ) : null);
+          didWarnAboutMaps = true;
+        }
+        // Iterator will provide entry [k,v] tuples rather than values.
+        while (!(step = iterator.next()).done) {
+          var entry = step.value;
+          if (entry) {
+            child = entry[1];
+            nextName = (
+              (nameSoFar !== '' ? nameSoFar + SUBSEPARATOR : SEPARATOR) +
+              wrapUserProvidedKey(entry[0]) + SUBSEPARATOR +
+              getComponentKey(child, 0)
+            );
+            nextIndex = indexSoFar + subtreeCount;
+            subtreeCount += traverseAllChildrenImpl(
+              child,
+              nextName,
+              nextIndex,
+              callback,
+              traverseContext
+            );
+          }
+        }
+      }
+    } else if (type === 'object') {
+      ("production" !== process.env.NODE_ENV ? invariant(
+        children.nodeType !== 1,
+        'traverseAllChildren(...): Encountered an invalid child; DOM ' +
+        'elements are not valid children of React components.'
+      ) : invariant(children.nodeType !== 1));
+      var fragment = ReactFragment.extract(children);
+      for (var key in fragment) {
+        if (fragment.hasOwnProperty(key)) {
+          child = fragment[key];
+          nextName = (
+            (nameSoFar !== '' ? nameSoFar + SUBSEPARATOR : SEPARATOR) +
+            wrapUserProvidedKey(key) + SUBSEPARATOR +
+            getComponentKey(child, 0)
+          );
+          nextIndex = indexSoFar + subtreeCount;
+          subtreeCount += traverseAllChildrenImpl(
+            child,
+            nextName,
+            nextIndex,
+            callback,
+            traverseContext
+          );
+        }
+      }
+    }
+  }
+
+  return subtreeCount;
+}
+
+/**
+ * Traverses children that are typically specified as `props.children`, but
+ * might also be specified through attributes:
+ *
+ * - `traverseAllChildren(this.props.children, ...)`
+ * - `traverseAllChildren(this.props.leftPanelChildren, ...)`
+ *
+ * The `traverseContext` is an optional argument that is passed through the
+ * entire traversal. It can be used to store accumulations or anything else that
+ * the callback might find relevant.
+ *
+ * @param {?*} children Children tree object.
+ * @param {!function} callback To invoke upon traversing each child.
+ * @param {?*} traverseContext Context for traversal.
+ * @return {!number} The number of children in this subtree.
+ */
+function traverseAllChildren(children, callback, traverseContext) {
+  if (children == null) {
+    return 0;
+  }
+
+  return traverseAllChildrenImpl(children, '', 0, callback, traverseContext);
+}
+
+module.exports = traverseAllChildren;