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'use strict';
const pLimit = require('p-limit');
class EndError extends Error {
constructor(value) {
super();
this.value = value;
}
}
// The input can also be a promise, so we await it
const testElement = async (element, tester) => tester(await element);
// The input can also be a promise, so we `Promise.all()` them both
const finder = async element => {
const values = await Promise.all(element);
if (values[1] === true) {
throw new EndError(values[0]);
}
return false;
};
const pLocate = async (iterable, tester, options) => {
options = {
concurrency: Infinity,
preserveOrder: true,
...options
};
const limit = pLimit(options.concurrency);
// Start all the promises concurrently with optional limit
const items = [...iterable].map(element => [element, limit(testElement, element, tester)]);
// Check the promises either serially or concurrently
const checkLimit = pLimit(options.preserveOrder ? 1 : Infinity);
try {
await Promise.all(items.map(element => checkLimit(finder, element)));
} catch (error) {
if (error instanceof EndError) {
return error.value;
}
throw error;
}
};
module.exports = pLocate;
// TODO: Remove this for the next major release
module.exports.default = pLocate;
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