react-native/Libraries/ReactNative/findNodeHandle.js

113 lines
4.0 KiB
JavaScript

/**
* Copyright (c) 2015-present, 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 findNodeHandle
* @flow
*/
'use strict';
var ReactCurrentOwner = require('ReactCurrentOwner');
var ReactInstanceMap = require('ReactInstanceMap');
var ReactNativeTagHandles = require('ReactNativeTagHandles');
var invariant = require('invariant');
var warning = require('warning');
/**
* ReactNative vs ReactWeb
* -----------------------
* React treats some pieces of data opaquely. This means that the information
* is first class (it can be passed around), but cannot be inspected. This
* allows us to build infrastructure that reasons about resources, without
* making assumptions about the nature of those resources, and this allows that
* infra to be shared across multiple platforms, where the resources are very
* different. General infra (such as `ReactMultiChild`) reasons opaquely about
* the data, but platform specific code (such as `ReactNativeBaseComponent`) can
* make assumptions about the data.
*
*
* `rootNodeID`, uniquely identifies a position in the generated native view
* tree. Many layers of composite components (created with `React.createClass`)
* can all share the same `rootNodeID`.
*
* `nodeHandle`: A sufficiently unambiguous way to refer to a lower level
* resource (dom node, native view etc). The `rootNodeID` is sufficient for web
* `nodeHandle`s, because the position in a tree is always enough to uniquely
* identify a DOM node (we never have nodes in some bank outside of the
* document). The same would be true for `ReactNative`, but we must maintain a
* mapping that we can send efficiently serializable
* strings across native boundaries.
*
* Opaque name TodaysWebReact FutureWebWorkerReact ReactNative
* ----------------------------------------------------------------------------
* nodeHandle N/A rootNodeID tag
*/
function findNodeHandle(componentOrHandle: any): ?number {
if (__DEV__) {
var owner = ReactCurrentOwner.current;
if (owner !== null) {
warning(
owner._warnedAboutRefsInRender,
'%s is accessing findNodeHandle inside its render(). ' +
'render() should be a pure function of props and state. It should ' +
'never access something that requires stale data from the previous ' +
'render, such as refs. Move this logic to componentDidMount and ' +
'componentDidUpdate instead.',
owner.getName() || 'A component'
);
owner._warnedAboutRefsInRender = true;
}
}
if (componentOrHandle == null) {
return null;
}
if (typeof componentOrHandle === 'number') {
// Already a node handle
return componentOrHandle;
}
var component = componentOrHandle;
// TODO (balpert): Wrap iOS native components in a composite wrapper, then
// ReactInstanceMap.get here will always succeed for mounted components
var internalInstance = ReactInstanceMap.get(component);
if (internalInstance) {
return ReactNativeTagHandles.rootNodeIDToTag[internalInstance._rootNodeID];
} else {
var rootNodeID = component._rootNodeID;
if (rootNodeID) {
return ReactNativeTagHandles.rootNodeIDToTag[rootNodeID];
} else {
invariant(
(
// Native
typeof component === 'object' &&
'_rootNodeID' in component
) || (
// Composite
component.render != null &&
typeof component.render === 'function'
),
'findNodeHandle(...): Argument is not a component ' +
'(type: %s, keys: %s)',
typeof component,
Object.keys(component)
);
invariant(
false,
'findNodeHandle(...): Unable to find node handle for unmounted ' +
'component.'
);
}
}
}
module.exports = findNodeHandle;