87 lines
2.2 KiB
JavaScript
87 lines
2.2 KiB
JavaScript
|
"use strict";
|
||
|
|
|
||
|
|
// Returns "Type(value) is Object" in ES terminology.
|
||
|
|
function isObject(value) {
|
||
|
|
return typeof value === "object" && value !== null || typeof value === "function";
|
||
|
|
}
|
||
|
|
|
||
|
|
function getReferenceToBytes(bufferSource) {
|
||
|
|
// Node.js' Buffer does not allow subclassing for now, so we can get away with a prototype object check for perf.
|
||
|
|
if (Object.getPrototypeOf(bufferSource) === Buffer.prototype) {
|
||
|
|
return bufferSource;
|
||
|
|
}
|
||
|
|
if (bufferSource instanceof ArrayBuffer) {
|
||
|
|
return Buffer.from(bufferSource);
|
||
|
|
}
|
||
|
|
return Buffer.from(bufferSource.buffer, bufferSource.byteOffset, bufferSource.byteLength);
|
||
|
|
}
|
||
|
|
|
||
|
|
function getCopyToBytes(bufferSource) {
|
||
|
|
return Buffer.from(getReferenceToBytes(bufferSource));
|
||
|
|
}
|
||
|
|
|
||
|
|
function mixin(target, source) {
|
||
|
|
const keys = Object.getOwnPropertyNames(source);
|
||
|
|
for (let i = 0; i < keys.length; ++i) {
|
||
|
|
if (keys[i] in target) {
|
||
|
|
continue;
|
||
|
|
}
|
||
|
|
|
||
|
|
Object.defineProperty(target, keys[i], Object.getOwnPropertyDescriptor(source, keys[i]));
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
const wrapperSymbol = Symbol("wrapper");
|
||
|
|
const implSymbol = Symbol("impl");
|
||
|
|
const sameObjectCaches = Symbol("SameObject caches");
|
||
|
|
|
||
|
|
function getSameObject(wrapper, prop, creator) {
|
||
|
|
if (!wrapper[sameObjectCaches]) {
|
||
|
|
wrapper[sameObjectCaches] = Object.create(null);
|
||
|
|
}
|
||
|
|
|
||
|
|
if (prop in wrapper[sameObjectCaches]) {
|
||
|
|
return wrapper[sameObjectCaches][prop];
|
||
|
|
}
|
||
|
|
|
||
|
|
wrapper[sameObjectCaches][prop] = creator();
|
||
|
|
return wrapper[sameObjectCaches][prop];
|
||
|
|
}
|
||
|
|
|
||
|
|
function wrapperForImpl(impl) {
|
||
|
|
return impl ? impl[wrapperSymbol] : null;
|
||
|
|
}
|
||
|
|
|
||
|
|
function implForWrapper(wrapper) {
|
||
|
|
return wrapper ? wrapper[implSymbol] : null;
|
||
|
|
}
|
||
|
|
|
||
|
|
function tryWrapperForImpl(impl) {
|
||
|
|
const wrapper = wrapperForImpl(impl);
|
||
|
|
return wrapper ? wrapper : impl;
|
||
|
|
}
|
||
|
|
|
||
|
|
function tryImplForWrapper(wrapper) {
|
||
|
|
const impl = implForWrapper(wrapper);
|
||
|
|
return impl ? impl : wrapper;
|
||
|
|
}
|
||
|
|
|
||
|
|
const iterInternalSymbol = Symbol("internal");
|
||
|
|
const IteratorPrototype = Object.getPrototypeOf(Object.getPrototypeOf([][Symbol.iterator]()));
|
||
|
|
|
||
|
|
module.exports = exports = {
|
||
|
|
isObject,
|
||
|
|
getReferenceToBytes,
|
||
|
|
getCopyToBytes,
|
||
|
|
mixin,
|
||
|
|
wrapperSymbol,
|
||
|
|
implSymbol,
|
||
|
|
getSameObject,
|
||
|
|
wrapperForImpl,
|
||
|
|
implForWrapper,
|
||
|
|
tryWrapperForImpl,
|
||
|
|
tryImplForWrapper,
|
||
|
|
iterInternalSymbol,
|
||
|
|
IteratorPrototype
|
||
|
|
};
|