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/**
* @license
* Copyright The Closure Library Authors.
* SPDX-License-Identifier: Apache-2.0
*/
/**
* @fileoverview Provides some utility methods for calling delegate lists with
* common "calling conventions".
*
* @see goog.delegate.DelegateRegistry
*/
goog.module('goog.delegate.delegates');
/**
* Calls the first delegate, or returns undefined if none are given.
* @param {!Array<T>} delegates
* @param {function(T): R} mapper
* @return {R|undefined}
* @template T, R
*/
exports.callFirst = (delegates, mapper) => {
if (delegates.length === 0) {
return undefined;
}
return mapper(delegates[0]);
};
/**
* Calls delegates until one returns a defined, non-null result. Returns
* undefined if no such element is found.
* @param {!Array<T>} delegates
* @param {function(T): R|undefined} mapper
* @return {R|undefined}
* @template T, R
*/
exports.callUntilDefinedAndNotNull = (delegates, mapper) => {
for (const delegate of delegates) {
const result = mapper(delegate);
if (result != null) return result;
}
return undefined;
};
/**
* Calls delegates until one returns a truthy result. Returns false if no such
* element is found.
* @param {!Array<T>} delegates
* @param {function(T): R} mapper
* @return {boolean|R}
* @template T, R
*/
exports.callUntilTruthy = (delegates, mapper) => {
for (const delegate of delegates) {
const result = mapper(delegate);
if (result) return result;
}
return false;
};
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