mirror of
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68 lines
2.3 KiB
JavaScript
68 lines
2.3 KiB
JavaScript
/**
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* @license
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* Copyright 2019 Google LLC
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* SPDX-License-Identifier: Apache-2.0
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*/
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/**
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* @fileoverview Fields can be created based on a JSON definition. This file
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* contains methods for registering those JSON definitions, and building the
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* fields based on JSON.
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* @author bekawestberg@gmail.com (Beka Westberg)
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*/
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'use strict';
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goog.provide('Blockly.fieldRegistry');
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goog.require('Blockly.registry');
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goog.requireType('Blockly.Field');
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goog.requireType('Blockly.IRegistrableField');
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/**
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* Registers a field type.
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* Blockly.fieldRegistry.fromJson uses this registry to
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* find the appropriate field type.
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* @param {string} type The field type name as used in the JSON definition.
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* @param {!Blockly.IRegistrableField} fieldClass The field class containing a
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* fromJson function that can construct an instance of the field.
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* @throws {Error} if the type name is empty, the field is already
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* registered, or the fieldClass is not an object containing a fromJson
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* function.
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*/
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Blockly.fieldRegistry.register = function(type, fieldClass) {
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Blockly.registry.register(Blockly.registry.Type.FIELD, type, fieldClass);
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};
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/**
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* Unregisters the field registered with the given type.
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* @param {string} type The field type name as used in the JSON definition.
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*/
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Blockly.fieldRegistry.unregister = function(type) {
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Blockly.registry.unregister(Blockly.registry.Type.FIELD, type);
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};
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/**
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* Construct a Field from a JSON arg object.
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* Finds the appropriate registered field by the type name as registered using
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* Blockly.fieldRegistry.register.
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* @param {!Object} options A JSON object with a type and options specific
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* to the field type.
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* @return {?Blockly.Field} The new field instance or null if a field wasn't
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* found with the given type name
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* @package
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*/
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Blockly.fieldRegistry.fromJson = function(options) {
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var fieldObject = /** @type {?Blockly.IRegistrableField} */ (
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Blockly.registry.getObject(Blockly.registry.Type.FIELD, options['type']));
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if (!fieldObject) {
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console.warn('Blockly could not create a field of type ' + options['type'] +
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'. The field is probably not being registered. This could be because' +
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' the file is not loaded, the field does not register itself (Issue' +
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' #1584), or the registration is not being reached.');
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return null;
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}
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return fieldObject.fromJson(options);
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};
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