I have the following code:
var tableRequiredList = [];
var requireListPath = [
'./slimShady.js',
'./chickaChicka.js'
];
var getRequires = function() {
for (var i = 0; i < requireListPath.length; i++) {
((requireNamePath) => {
try {
console.log("INSIDE LOOP RESULT", i, require(requireNamePath)().getName()); // Outputs correct result for the index ("ChickaChicka")
tableRequiredList.push({ "name": requireNamePath, "theReq": require(requireNamePath)() });
// tableRequiredList.push({ "name": requireNamePath, "theReq": ((thePath) => { return require(thePath)(); })(requireNamePath) }); // This also doesn't seem to work.
} catch(err) {
console.log("Error importing: ", requireNamePath, " Error reported: ", err);
}
})(requireListPath[i]);
};
console.log("NAME", tableRequiredList[0].name); // Outputs the correct result ("slimShady.js")
console.log("FUNC NAME", tableRequiredList[0].theReq.getName()); // Always outputs the last item in requireListPath list ("ChickaChicka")
};
getRequires();
Example Module 1 - slimShady.js
((module) => {
module.exports = {};
var exampleModuleName1 = function() {
this.getName = function() {
return 'myNameIsSlimShady';
};
return this;
};
module.exports = exampleModuleName1;
})(module);
Example Module 2 - chickaChicka.js
((module) => {
module.exports = {};
var exampleModuleName2 = function() {
this.getName = function() {
return 'ChickaChicka';
};
return this;
};
module.exports = exampleModuleName2;
})(module);
Why does it output:
INSIDE LOOP RESULT 0 myNameIsSlimShady
INSIDE LOOP RESULT 1 ChickaChicka
NAME ./slimShady.js
FUNC NAME ChickaChicka
When it should be outputting the first index of the tableRequiredList array? This seems to only happen with require(). I have tried using map and forEach, along with the closure example above. All have the same results.
Thanks to #liliscent, I figured it out.
Just needed to change modules to this:
((module) => {
module.exports = {};
var exampleModuleName2 = function() {
var retr = {};
retr.getName = function() {
return 'ChickaChicka';
};
return retr;
};
module.exports = exampleModuleName2;
})(module);
Related
I am trying to read some data from 2 different tables and parse a CSV file before rendering an ejs file.
I can get the data from both tables and from the CSV file but I seem to be unable to return the result.
Pretty sure this is a problem with the way I handle async execution but I fail to see what I am doing wrong.
I've spent the last 2 days reading about this (including the threads around here) and browsing but somehow the answer still escapes me.
First file - usercms.js
app.get('/userscms', function(req, res)
{
existingUsers.getExistingUsers()
.then(function(appUsers)
{
//global users array
//I can display these in my ejs file
globalAppUsers = appUsers;
})
.then(existingUsersAttributesQlik.getExistingUsersAttributesQlik())
.then(function(usersQlikAttributes)
{
//global user attributes array
//undefined data
globalUsersQlikAttributes = usersQlikAttributes;
})
.then(existingSuppliers.parseSuppliersCSV())
.then(function(supplierData)
{
//the result I am expecting
//this prints undefined
console.log(supplierData);
}).then(function()
{
res.render('userscms.ejs',
{
users: globalAppUsers,
attributes: globalUsersQlikAttributes
});
});
});
Second function - getxistingUsers.js (identical to the getExistingUsersAttributesQlik, except for the query)
var userData = [];
var appUsers = [];
(function (exports)
{
exports.getExistingUsers = function ()
{
return promisemysql.createConnection(dbconfig.development).then(function(conn)
{
var result = conn.query("SELECT id, username, firstName, lastName, email, phone, lastLogin, isAdmin, isValid, isPhoneValid, accountCreationDateTime FROM Users");
conn.end();
return result;
}).then(function(rows)
{
return rows;
}).then(function(rows)
{
if (rows.length)
{
userData = [];
appUsers = [];
rows.forEach(function (elem)
{
userData.push(_.toArray(elem));
});
for (i = 0; i < userData.length; i++)
{
var appUser = new appUserModel.AppUser(
userData[i][0],
userData[i][1],
userData[i][2],
userData[i][3],
userData[i][4],
userData[i][5],
userData[i][6],
userData[i][7],
userData[i][8],
userData[i][9],
userData[i][10]);
appUsers.push(_.toArray(appUser));
}
return appUsers;
}
else
{
console.log("NOPE");
return null;
}
}).then(function(appUsers)
{
console.log(appUsers);
return appUsers;
});
};
})(typeof exports === 'undefined' ? this['getExistingUsers'] = {} : exports);
Third file - parseSuppliersCSV.js
var supplierData = [];
var suppliersData = [];
var csvCount = 0;
(function (exports)
{
exports.parseSuppliersCSV = function ()
{
return new Promise(function(resolve, reject)
{
var fileStream = fs.createReadStream("myCSV.csv");
var parser = fastCsv();
csvCount = 0;
supplierData = [];
suppliersData = [];
fileStream
.on("readable", function ()
{
var data;
while ((data = fileStream.read()) !== null)
{
parser.write(data);
}
})
.on("end", function ()
{
parser.end();
});
parser
.on("readable", function ()
{
var data;
while ((data = parser.read()) !== null)
{
if(csvCount >= 1)
{
csvCount++;
var arrayOfStrings = data[0].split(';');
var supplier = new supplierModel.Supplier(arrayOfStrings[0],arrayOfStrings[1]);
suppliersData.push(_.toArray(supplier));
}
else
{
csvCount++;
}
}
})
.on("end", function ()
{
console.log("done");
//all OK here
console.log(suppliersData);
//this doesn't seem to return anything
return suppliersData;
});
});
};
})(typeof exports === 'undefined' ? this['parseSuppliersCSV'] = {} : exports);
Any ideas what I am doing wrong? Am I approaching this the wrong way?
I'll take a guess here and assume the promise you created should resolve to something...instead of returning a value.
.on("end", function ()
{
console.log("done");
//all OK here
console.log(suppliersData);
//this doesn't seem to return anything
return resolve(suppliersData);
});
I have a module where when each function is executed, it reassigns the value of the variable. This variable is stored in the constructor as I want to use it across modules. How can I do this without repeating myself?
function FormatText(data) {
this._data = data;
}
FormatText.prototype.toDowncase = function() {
return this._data = this._data.toLowerCase();
};
FormatText.prototype.deleteWords = function() {
return this._data = this._data.replace(/\W/g, " ");
};
FormatText.prototype.splitWords = function() {
return this._data = this._data.split(/\s+/);
};
FormatText.prototype.filterEntries = function() {
return this._data = this._data.filter(v => !!v);
};
FormatText.prototype.countWords = function() {
return this._data = this._data.reduce((dict, v) => {dict[v] = v in dict ? dict[v] + 1 : 1; return dict}, {});
}
module.exports = FormatText;
I can't get toBeCalled() working in my Jade test script.
I get the following error msg when run the Jade test:
Error: toBeCalled() should be used on a mock function or a jasmine spy
I have a call to jest.unmock('../fooey') so not sure why I'm getting the error ?
fooey.js
var foo = function(phrase) {
return bar(phrase);
}
var bar = function(greeting) {
console.log(greeting + " Watz up?");
}
foo("Hi Bob!");
module.exports.foo = foo;
module.exports.bar = bar;
fooey-test.js:
jest.unmock('../fooey'); // unmock to use the actual implementation.
describe('fooey()', () => {
const foo = require('../fooey').foo;
const bar = require('../fooey').bar;
it('bar() is called.', () => {
foo("Hi Bob!");
expect(bar).toBeCalled();
});
});
I got it working with both a mock of bar() and also using spyOn()...
fooey.js
var Fooey = function() {
// var self = this;
this.foo = function(phrase) {
// var result = self.bar(phrase);
var result = this.bar(phrase);
return result;
// return "Junky."
};
this.bar = function(greeting) {
var result = greeting + " Watz up?"
console.log(result);
return result;
};
};
module.exports = Fooey;
fooey-test.js
jest.unmock('../fooey'); // unmock to use the actual implementation.
describe('fooey()', () => {
const Fooey = require('../fooey');
const fooey = new Fooey();
it('mock: bar() is called.', () => {
var myFooey = {
foo: fooey.foo,
bar: jest.genMockFunction()
};
myFooey.foo("Hello");
expect(myFooey.bar).toBeCalledWith("Hello");
});
it('bar() is called with "Hi Bob!".', () => {
spyOn(fooey, 'bar');
fooey.foo("Hi Bob!");
expect(fooey.bar).toHaveBeenCalledWith("Hi Bob!");
});
});
I'm constructing a Builder in JavaScript, and I'm not sure how builders normally handle undefined values for optionals. I would like to think that the Builder doesn't append the optional field to the object if the field is undefined. Is that acceptable for a Builder? If not, what would be alternatives?
Here is a sample of the first implementation where the builder doesn't append an undefined optional:
Builder:
function Thing(required1, required2, required3) {
//check required params
var fields = {
required1: required1,
required2: required2,
required3: required3
};
var _withOptionalParam = function(param) {
if(!param) { return this; } //exit function early if param is undefined
fields.param = param;
return this;
};
var _build = function() {
var result = fields;
return result;
};
var builder = {
withOptionalParam: _withOptionalParam,
build: _build
};
return builder;
}
In action:
var thing = new Thing("foo","bar","baz").withOptionalParam(undefined).build();
//'thing' should be
// {
// required1:"foo",
// required2:"bar",
// required3:"baz"
// };
//
Thanks in advance!
I think you are losing the context of this in your _withOptinalParam function. You could bind you fields object to it as the this context.
function Thing(required1, required2, required3) {
//check required params
var fields = {
required1: required1,
required2: required2,
required3: required3
};
var _withOptionalParam = function(param) {
if(!param) { return this; } //exit function early if param is undefined
fields.param = param;
return this;
};
var _build = function() {
var result = fields;
return result;
};
var builder = {
withOptionalParam: _withOptionalParam.bind(fields),
build: _build
};
return builder;
}
var thing = new Thing("foo","bar","baz").withOptionalParam(undefined);
console.log( thing );
//'thing' should be
// {
// required1:"foo",
// required2:"bar",
// required3:"baz"
// };
//
<script src="http://codepen.io/synthet1c/pen/WrQapG.js"></script>
I have a sealed object with an array member on which I want to prevent direct pushes.
var myModule = (function () {
"use strict";
var a = (function () {
var _b = {},
_c = _c = "",
_d = [];
Object.defineProperty(_b, "c", {
get: function () { return _c; }
});
Object.defineProperty(_b, "d", {
get { return _d; }
});
_b.addD = function (newD) {
_d.push(newD);
};
Object.seal(_b);
return _b;
}());
var _something = { B: _b };
return {
Something: _something,
AddD: _b.addD
};
}());
myModule.Something.c = "blah"; // doesn't update = WIN!!
myModule.AddD({}); // pushed = WIN!
myModule.Something.d.push({}); // pushed = sadness
How can I prevent the push?
UPDATE:
Thanks for all the thoughts. I eventually need the JSON to send to the server. It looks like I might need to use an object for the array then figure out a way to generate and return the JSON needed, or change _something to use .slice(). Will play and report.
you could override the push method:
var _d = [];
_d.__proto__.push = function() { return this.length; }
and when you need to use it in your module, call Array.prototype.push:
_b.addD = function (newD) {
Array.prototype.push.call(_d, newD);
};
I haven't done any performance tests on this, but this certainly helps to protect your array.
(function(undefined) {
var protectedArrays = [];
protectArray = function protectArray(arr) {
protectedArrays.push(arr);
return getPrivateUpdater(arr);
}
var isProtected = function(arr) {
return protectedArrays.indexOf(arr)>-1;
}
var getPrivateUpdater = function(arr) {
var ret = {};
Object.keys(funcBackups).forEach(function(funcName) {
ret[funcName] = funcBackups[funcName].bind(arr);
});
return ret;
}
var returnsNewArray = ['Array.prototype.splice'];
var returnsOriginalArray = ['Array.prototype.fill','Array.prototype.reverse','Array.prototype.copyWithin','Array.prototype.sort'];
var returnsLength = ['Array.prototype.push','Array.prototype.unshift'];
var returnsValue = ['Array.prototype.shift','Array.prototype.pop'];
var funcBackups = {};
overwriteFuncs(returnsNewArray, function() { return []; });
overwriteFuncs(returnsOriginalArray, function() { return this; });
overwriteFuncs(returnsLength, function() { return this.length; });
overwriteFuncs(returnsValue, function() { return undefined; });
function overwriteFuncs(funcs, ret) {
for(var i=0,c=funcs.length;i<c;i++)
{
var func = funcs[i];
var funcParts = func.split('.');
var obj = window;
for(var j=0,l=funcParts.length;j<l;j++)
{
(function() {
var part = funcParts[j];
if(j!=l-1) obj = obj[part];
else if(typeof obj[part] === "function")
{
var funcBk = obj[part];
funcBackups[funcBk.name] = funcBk;
obj[part] = renameFunction(funcBk.name, function() {
if(isProtected(this)) return ret.apply(this, arguments);
else return funcBk.apply(this,arguments);
});
}
})();
}
}
}
function renameFunction(name, fn) {
return (new Function("return function (call) { return function " + name +
" () { return call(this, arguments) }; };")())(Function.apply.bind(fn));
};
})();
You would use it like so:
var myArr = [];
var myArrInterface = protectArray(myArr);
myArr.push(5); //Doesn't work, but returns length as expected
myArrInterface.push(5); //Works as normal
This way, you can internally keep a copy of the interface that isn't made global to allow your helper funcs to modify the array as normal, but any attempt to use .push .splice etc will fail, either directly, or using the .bind(myArr,arg) method.
It's still not completely watertight, but a pretty good protector. You could potentially use the Object.defineProperty method to generate protected properties for the first 900 indexes, but I'm not sure of the implications of this. There is also the method Object.preventExtensions() but I'm unaware of a way to undo this effect when you need to change it yourself
Thank you, dandavis!
I used the slice method:
var myModule = (function () {
"use strict";
var a = (function () {
var _b = {},
_c = _c = "",
_d = [];
Object.defineProperty(_b, "c", {
get: function () { return _c; }
});
Object.defineProperty(_b, "d", {
get { return _d.slice(); } // UPDATED
});
_b.updateC = function (newValue) {
_c = newValue;
};
_b.addD = function (newD) {
_d.push(newD);
};
Object.seal(_b);
return _b;
}());
var _something = { B: _b };
return {
Something: _something,
AddD: _b.addD
};
}());
myModule.Something.c = "blah"; // doesn't update = WIN!!
myModule.AddD({}); // pushed = WIN!
myModule.Something.d.push({}); // no more update = happiness
This allows me to protect from direct push calls enforcing some logic.