2025-04-01 23:48:10 -04:00

139 lines
2.8 KiB
JavaScript

'use strict';
const from = require('from2');
const pIsPromise = require('p-is-promise');
const intoStream = input => {
if (Array.isArray(input)) {
input = input.slice();
}
let promise;
let iterator;
let asyncIterator;
prepare(input);
function prepare(value) {
input = value;
if (
input instanceof ArrayBuffer ||
(ArrayBuffer.isView(input) && !Buffer.isBuffer(input))
) {
input = Buffer.from(input);
}
promise = pIsPromise(input) ? input : null;
// We don't iterate on strings and buffers since slicing them is ~7x faster
const shouldIterate = !promise && input[Symbol.iterator] && typeof input !== 'string' && !Buffer.isBuffer(input);
iterator = shouldIterate ? input[Symbol.iterator]() : null;
const shouldAsyncIterate = !promise && input[Symbol.asyncIterator];
asyncIterator = shouldAsyncIterate ? input[Symbol.asyncIterator]() : null;
}
return from(function reader(size, callback) {
if (promise) {
(async () => {
try {
await prepare(await promise);
reader.call(this, size, callback);
} catch (error) {
callback(error);
}
})();
return;
}
if (iterator) {
const object = iterator.next();
setImmediate(callback, null, object.done ? null : object.value);
return;
}
if (asyncIterator) {
(async () => {
try {
const object = await asyncIterator.next();
setImmediate(callback, null, object.done ? null : object.value);
} catch (error) {
setImmediate(callback, error);
}
})();
return;
}
if (input.length === 0) {
setImmediate(callback, null, null);
return;
}
const chunk = input.slice(0, size);
input = input.slice(size);
setImmediate(callback, null, chunk);
});
};
module.exports = intoStream;
module.exports.object = input => {
if (Array.isArray(input)) {
input = input.slice();
}
let promise;
let iterator;
let asyncIterator;
prepare(input);
function prepare(value) {
input = value;
promise = pIsPromise(input) ? input : null;
iterator = !promise && input[Symbol.iterator] ? input[Symbol.iterator]() : null;
asyncIterator = !promise && input[Symbol.asyncIterator] ? input[Symbol.asyncIterator]() : null;
}
return from.obj(function reader(size, callback) {
if (promise) {
(async () => {
try {
await prepare(await promise);
reader.call(this, size, callback);
} catch (error) {
callback(error);
}
})();
return;
}
if (iterator) {
const object = iterator.next();
setImmediate(callback, null, object.done ? null : object.value);
return;
}
if (asyncIterator) {
(async () => {
try {
const object = await asyncIterator.next();
setImmediate(callback, null, object.done ? null : object.value);
} catch (error) {
setImmediate(callback, error);
}
})();
return;
}
this.push(input);
setImmediate(callback, null, null);
});
};