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rOACCT/node_modules/gensync/index.js
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"use strict";
// These use the global symbol registry so that multiple copies of this
// library can work together in case they are not deduped.
const GENSYNC_START = Symbol.for("gensync:v1:start");
const GENSYNC_SUSPEND = Symbol.for("gensync:v1:suspend");
const GENSYNC_EXPECTED_START = "GENSYNC_EXPECTED_START";
const GENSYNC_EXPECTED_SUSPEND = "GENSYNC_EXPECTED_SUSPEND";
const GENSYNC_OPTIONS_ERROR = "GENSYNC_OPTIONS_ERROR";
const GENSYNC_RACE_NONEMPTY = "GENSYNC_RACE_NONEMPTY";
const GENSYNC_ERRBACK_NO_CALLBACK = "GENSYNC_ERRBACK_NO_CALLBACK";
module.exports = Object.assign(
function gensync(optsOrFn) {
let genFn = optsOrFn;
if (typeof optsOrFn !== "function") {
genFn = newGenerator(optsOrFn);
} else {
genFn = wrapGenerator(optsOrFn);
}
return Object.assign(genFn, makeFunctionAPI(genFn));
},
{
all: buildOperation({
name: "all",
arity: 1,
sync: function(args) {
const items = Array.from(args[0]);
return items.map(item => evaluateSync(item));
},
async: function(args, resolve, reject) {
const items = Array.from(args[0]);
if (items.length === 0) {
Promise.resolve().then(() => resolve([]));
return;
}
let count = 0;
const results = items.map(() => undefined);
items.forEach((item, i) => {
evaluateAsync(
item,
val => {
results[i] = val;
count += 1;
if (count === results.length) resolve(results);
},
reject
);
});
},
}),
race: buildOperation({
name: "race",
arity: 1,
sync: function(args) {
const items = Array.from(args[0]);
if (items.length === 0) {
throw makeError("Must race at least 1 item", GENSYNC_RACE_NONEMPTY);
}
return evaluateSync(items[0]);
},
async: function(args, resolve, reject) {
const items = Array.from(args[0]);
if (items.length === 0) {
throw makeError("Must race at least 1 item", GENSYNC_RACE_NONEMPTY);
}
for (const item of items) {
evaluateAsync(item, resolve, reject);
}
},
}),
}
);
/**
* Given a generator function, return the standard API object that executes
* the generator and calls the callbacks.
*/
function makeFunctionAPI(genFn) {
const fns = {
sync: function(...args) {
return evaluateSync(genFn.apply(this, args));
},
async: function(...args) {
return new Promise((resolve, reject) => {
evaluateAsync(genFn.apply(this, args), resolve, reject);
});
},
errback: function(...args) {
const cb = args.pop();
if (typeof cb !== "function") {
throw makeError(
"Asynchronous function called without callback",
GENSYNC_ERRBACK_NO_CALLBACK
);
}
let gen;
try {
gen = genFn.apply(this, args);
} catch (err) {
cb(err);
return;
}
evaluateAsync(gen, val => cb(undefined, val), err => cb(err));
},
};
return fns;
}
function assertTypeof(type, name, value, allowUndefined) {
if (
typeof value === type ||
(allowUndefined && typeof value === "undefined")
) {
return;
}
let msg;
if (allowUndefined) {
msg = `Expected opts.${name} to be either a ${type}, or undefined.`;
} else {
msg = `Expected opts.${name} to be a ${type}.`;
}
throw makeError(msg, GENSYNC_OPTIONS_ERROR);
}
function makeError(msg, code) {
return Object.assign(new Error(msg), { code });
}
/**
* Given an options object, return a new generator that dispatches the
* correct handler based on sync or async execution.
*/
function newGenerator({ name, arity, sync, async, errback }) {
assertTypeof("string", "name", name, true /* allowUndefined */);
assertTypeof("number", "arity", arity, true /* allowUndefined */);
assertTypeof("function", "sync", sync);
assertTypeof("function", "async", async, true /* allowUndefined */);
assertTypeof("function", "errback", errback, true /* allowUndefined */);
if (async && errback) {
throw makeError(
"Expected one of either opts.async or opts.errback, but got _both_.",
GENSYNC_OPTIONS_ERROR
);
}
if (typeof name !== "string") {
let fnName;
if (errback && errback.name && errback.name !== "errback") {
fnName = errback.name;
}
if (async && async.name && async.name !== "async") {
fnName = async.name.replace(/Async$/, "");
}
if (sync && sync.name && sync.name !== "sync") {
fnName = sync.name.replace(/Sync$/, "");
}
if (typeof fnName === "string") {
name = fnName;
}
}
if (typeof arity !== "number") {
arity = sync.length;
}
return buildOperation({
name,
arity,
sync: function(args) {
return sync.apply(this, args);
},
async: function(args, resolve, reject) {
if (async) {
async.apply(this, args).then(resolve, reject);
} else if (errback) {
errback.call(this, ...args, (err, value) => {
if (err == null) resolve(value);
else reject(err);
});
} else {
resolve(sync.apply(this, args));
}
},
});
}
function wrapGenerator(genFn) {
return setFunctionMetadata(genFn.name, genFn.length, function(...args) {
return genFn.apply(this, args);
});
}
function buildOperation({ name, arity, sync, async }) {
return setFunctionMetadata(name, arity, function*(...args) {
const resume = yield GENSYNC_START;
if (!resume) {
// Break the tail call to avoid a bug in V8 v6.X with --harmony enabled.
const res = sync.call(this, args);
return res;
}
let result;
try {
async.call(
this,
args,
value => {
if (result) return;
result = { value };
resume();
},
err => {
if (result) return;
result = { err };
resume();
}
);
} catch (err) {
result = { err };
resume();
}
// Suspend until the callbacks run. Will resume synchronously if the
// callback was already called.
yield GENSYNC_SUSPEND;
if (result.hasOwnProperty("err")) {
throw result.err;
}
return result.value;
});
}
function evaluateSync(gen) {
let value;
while (!({ value } = gen.next()).done) {
assertStart(value, gen);
}
return value;
}
function evaluateAsync(gen, resolve, reject) {
(function step() {
try {
let value;
while (!({ value } = gen.next()).done) {
assertStart(value, gen);
// If this throws, it is considered to have broken the contract
// established for async handlers. If these handlers are called
// synchronously, it is also considered bad behavior.
let sync = true;
let didSyncResume = false;
const out = gen.next(() => {
if (sync) {
didSyncResume = true;
} else {
step();
}
});
sync = false;
assertSuspend(out, gen);
if (!didSyncResume) {
// Callback wasn't called synchronously, so break out of the loop
// and let it call 'step' later.
return;
}
}
return resolve(value);
} catch (err) {
return reject(err);
}
})();
}
function assertStart(value, gen) {
if (value === GENSYNC_START) return;
throwError(
gen,
makeError(
`Got unexpected yielded value in gensync generator: ${JSON.stringify(
value
)}. Did you perhaps mean to use 'yield*' instead of 'yield'?`,
GENSYNC_EXPECTED_START
)
);
}
function assertSuspend({ value, done }, gen) {
if (!done && value === GENSYNC_SUSPEND) return;
throwError(
gen,
makeError(
done
? "Unexpected generator completion. If you get this, it is probably a gensync bug."
: `Expected GENSYNC_SUSPEND, got ${JSON.stringify(
value
)}. If you get this, it is probably a gensync bug.`,
GENSYNC_EXPECTED_SUSPEND
)
);
}
function throwError(gen, err) {
// Call `.throw` so that users can step in a debugger to easily see which
// 'yield' passed an unexpected value. If the `.throw` call didn't throw
// back to the generator, we explicitly do it to stop the error
// from being swallowed by user code try/catches.
if (gen.throw) gen.throw(err);
throw err;
}
function isIterable(value) {
return (
!!value &&
(typeof value === "object" || typeof value === "function") &&
!value[Symbol.iterator]
);
}
function setFunctionMetadata(name, arity, fn) {
if (typeof name === "string") {
// This should always work on the supported Node versions, but for the
// sake of users that are compiling to older versions, we check for
// configurability so we don't throw.
const nameDesc = Object.getOwnPropertyDescriptor(fn, "name");
if (!nameDesc || nameDesc.configurable) {
Object.defineProperty(
fn,
"name",
Object.assign(nameDesc || {}, {
configurable: true,
value: name,
})
);
}
}
if (typeof arity === "number") {
const lengthDesc = Object.getOwnPropertyDescriptor(fn, "length");
if (!lengthDesc || lengthDesc.configurable) {
Object.defineProperty(
fn,
"length",
Object.assign(lengthDesc || {}, {
configurable: true,
value: arity,
})
);
}
}
return fn;
}
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