Current File : /home/opti/workflow/node_modules/memoizee/ext/promise.js
/* eslint max-statements: 0 */
// Support for functions returning promise
"use strict";
var objectMap = require("es5-ext/object/map")
, primitiveSet = require("es5-ext/object/primitive-set")
, ensureString = require("es5-ext/object/validate-stringifiable-value")
, toShortString = require("es5-ext/to-short-string-representation")
, isPromise = require("is-promise")
, nextTick = require("next-tick");
var create = Object.create
, supportedModes = primitiveSet("then", "then:finally", "done", "done:finally");
require("../lib/registered-extensions").promise = function (mode, conf) {
var waiting = create(null), cache = create(null), promises = create(null);
if (mode === true) {
mode = null;
} else {
mode = ensureString(mode);
if (!supportedModes[mode]) {
throw new TypeError("'" + toShortString(mode) + "' is not valid promise mode");
}
}
// After not from cache call
conf.on("set", function (id, ignore, promise) {
var isFailed = false;
if (!isPromise(promise)) {
// Non promise result
cache[id] = promise;
conf.emit("setasync", id, 1);
return;
}
waiting[id] = 1;
promises[id] = promise;
var onSuccess = function (result) {
var count = waiting[id];
if (isFailed) {
throw new Error(
"Memoizee error: Detected unordered then|done & finally resolution, which " +
"in turn makes proper detection of success/failure impossible (when in " +
"'done:finally' mode)\n" +
"Consider to rely on 'then' or 'done' mode instead."
);
}
if (!count) return; // Deleted from cache before resolved
delete waiting[id];
cache[id] = result;
conf.emit("setasync", id, count);
};
var onFailure = function () {
isFailed = true;
if (!waiting[id]) return; // Deleted from cache (or succeed in case of finally)
delete waiting[id];
delete promises[id];
conf.delete(id);
};
var resolvedMode = mode;
if (!resolvedMode) resolvedMode = "then";
if (resolvedMode === "then") {
var nextTickFailure = function () { nextTick(onFailure); };
// Eventual finally needs to be attached to non rejected promise
// (so we not force propagation of unhandled rejection)
promise = promise.then(function (result) {
nextTick(onSuccess.bind(this, result));
}, nextTickFailure);
// If `finally` is a function we attach to it to remove cancelled promises.
if (typeof promise.finally === "function") {
promise.finally(nextTickFailure);
}
} else if (resolvedMode === "done") {
// Not recommended, as it may mute any eventual "Unhandled error" events
if (typeof promise.done !== "function") {
throw new Error(
"Memoizee error: Retrieved promise does not implement 'done' " +
"in 'done' mode"
);
}
promise.done(onSuccess, onFailure);
} else if (resolvedMode === "done:finally") {
// The only mode with no side effects assuming library does not throw unconditionally
// for rejected promises.
if (typeof promise.done !== "function") {
throw new Error(
"Memoizee error: Retrieved promise does not implement 'done' " +
"in 'done:finally' mode"
);
}
if (typeof promise.finally !== "function") {
throw new Error(
"Memoizee error: Retrieved promise does not implement 'finally' " +
"in 'done:finally' mode"
);
}
promise.done(onSuccess);
promise.finally(onFailure);
}
});
// From cache (sync)
conf.on("get", function (id, args, context) {
var promise;
if (waiting[id]) {
++waiting[id]; // Still waiting
return;
}
promise = promises[id];
var emit = function () { conf.emit("getasync", id, args, context); };
if (isPromise(promise)) {
if (typeof promise.done === "function") promise.done(emit);
else {
promise.then(function () { nextTick(emit); });
}
} else {
emit();
}
});
// On delete
conf.on("delete", function (id) {
delete promises[id];
if (waiting[id]) {
delete waiting[id];
return; // Not yet resolved
}
if (!hasOwnProperty.call(cache, id)) return;
var result = cache[id];
delete cache[id];
conf.emit("deleteasync", id, [result]);
});
// On clear
conf.on("clear", function () {
var oldCache = cache;
cache = create(null);
waiting = create(null);
promises = create(null);
conf.emit("clearasync", objectMap(oldCache, function (data) { return [data]; }));
});
};
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