com.google.javascript.jscomp.JsIterables Maven / Gradle / Ivy
/*
* Copyright 2014 The Closure Compiler Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.javascript.jscomp;
import static com.google.javascript.rhino.jstype.JSTypeNative.UNKNOWN_TYPE;
import com.google.javascript.rhino.jstype.JSType;
import com.google.javascript.rhino.jstype.JSTypeNative;
import com.google.javascript.rhino.jstype.JSTypeRegistry;
import com.google.javascript.rhino.jstype.TemplateTypeMap;
/**
* Models type transformations of JavaScript `Iterable` and `Iterator` types.
*
* These tranformations can be especially helpful when working with generator functions.
* `Generator` is a subtype of `Iterable`.
*/
final class JsIterables {
/**
* Returns the given `Iterable`s element type.
*
*
If the given type is not an `Iterator`, `Iterable`, `AsyncIterator`, or `AsyncIterable`,
* returns the unknown type.
*/
static final JSType getElementType(JSType iterableOrIterator, JSTypeRegistry typeRegistry) {
TemplateTypeMap templateTypeMap =
iterableOrIterator
// Remember that `string` will box to a `Iterable`.
.autobox()
.getTemplateTypeMap();
if (templateTypeMap.hasTemplateKey(typeRegistry.getIterableTemplate())) {
// `Iterable` or `Generator`
return templateTypeMap.getResolvedTemplateType(typeRegistry.getIterableTemplate());
} else if (templateTypeMap.hasTemplateKey(typeRegistry.getIteratorTemplate())) {
// `Iterator`
return templateTypeMap.getResolvedTemplateType(typeRegistry.getIteratorTemplate());
} else if (templateTypeMap.hasTemplateKey(typeRegistry.getAsyncIterableTemplate())) {
// `AsyncIterable` or `AsyncGenerator`
return templateTypeMap.getResolvedTemplateType(typeRegistry.getAsyncIterableTemplate());
} else if (templateTypeMap.hasTemplateKey(typeRegistry.getAsyncIteratorTemplate())) {
// `AsyncIterator`
return templateTypeMap.getResolvedTemplateType(typeRegistry.getAsyncIteratorTemplate());
}
return typeRegistry.getNativeType(UNKNOWN_TYPE);
}
/**
* Returns an `Iterable` type templated on {@code elementType}.
*
* Example: `number' => `Iterable`.
*/
static final JSType createIterableTypeOf(JSType elementType, JSTypeRegistry typeRegistry) {
return typeRegistry.createTemplatizedType(
typeRegistry.getNativeObjectType(JSTypeNative.ITERABLE_TYPE), elementType);
}
private JsIterables() {}
}