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Promise/Callback fn wrappers for then-pug (which is generators based)
//- will only work with the `npm install then-pug` module instead of default `pug`
//- passed in locals are: sendmail (node module), insp which is require('util').inspect, and just passed in Promise
-
// for functions having the second param as callback (e.g. nodejs fs.readFile)
function syncifyCb(fn) {
return function* (param1) {
let result = null;
yield function* () {
yield new Promise(function (ret) {
fn(
param1 || undefined,
function(err,data) { ret({err,data}); }
);
})
}().next().value.then(function(r) { result = r; });
return result;
}
};
//syncify
let sendmailSync = syncifyCb(sendmail);
//exec
let res = yield sendmailSync({
from: 'no-reply@test.test',
to: 'test@test.test',
subject: 'test sendmail',
html: 'Hello world.'
});
pre= insp(res)
-
// for directly wrapping a promise to await for
function syncifyPromise(fn) {
return function* () {
let result = null;
yield function* () {
yield fn
}().next().value.then(function(r) { result = r; });
return result;
}()
};
const start = Date.now(); // mesure the 1s
// new Promise stars resolving async the moment it is declared - syncify + exec
let res2 = yield syncifyPromise(
// test promise
new Promise( function(ret) {
setTimeout(function() {ret('sleep'); }, 1000); // 1s delay
})
);
const ms = Date.now() - start;
pre= insp(res2) + ` -> ${ms}ms`
-
// for typical facory functions returning a promise to be awaited for (e.g. node fs.promises.readFile)
function syncifyPromiseFactory(fn) {
return function* (param1) {
let result = null;
yield function* () {
yield fn(param1)
}().next().value.then(function(r) { result = r; });
return result;
}
};
// test factory
let makeX = function(options = {}) {
return new Promise( function(ret) {
setTimeout(function() {ret('sleep'); }, options.ms || 1000); // 1s delay
});
};
// syncify
let makeXSync = syncifyPromiseFactory(makeX);
const startX = Date.now(); // mesure the 1s
// exec
let res3 = yield makeX({ms: 500});
const msX = Date.now() - startX;
// example2 - passed in on locals: {.., CouchDB: nano(serviceUrlInclCreds), .. }
//let list = syncifyPromiseFactory( CouchDB.db.use('requests').list );
//let requests = yield list();
pre= insp(res3) + ` -> ${msX}ms`
div done
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