Tutorial by Examples: pre

// Set up Express var express = require('express'); var app = express(); /* Serve from the absolute path of the directory that you want to serve with a */ virtual path prefix app.use('/static', express.static(__dirname + '/public')); // Start Express server app.listen(3030);

preserveAspectRatio is an attribute that indicates whether the image should be scaled uniformly. This attribute only works if the <svg> element also has a viewBox. The default value is xMidYMid, which maintains the aspect ratio and centers the path inside the SVG container: <!-- when not ...

Operators that bound tighter (higher precedence) are listed first. OperatorsPrecedence group (≥3.0)PrecedenceAssociativity.∞left?, !, ++, --, [], (), {}(postfix)!, ~, +, -, ++, --(prefix)~> (swift ≤2.3)255left<<, >>BitwiseShiftPrecedence160none*, /, %, &, &*MultiplicationPrec...

s/foo/bar/; # replace "foo" with "bar" in $_ my $foo = "foo"; $foo =~ s/foo/bar/; # do the above on a different variable using the binding operator =~ s~ foo ~ bar ~; # using ~ as a delimiter $foo = s/foo/bar/r; # non-destructive r flag: returns the repl...

First, ensure you have installed mongodb and express via npm. Then, in a file conventionally titled db.js, use the following code: var MongoClient = require('mongodb').MongoClient var state = { db: null, } exports.connect = function(url, done) { if (state.db) return done() M...

Sql Server 2016+ and Azure Sql database enables you to automatically filter rows that are returned in select statement using some predicate. This feature is called Row-level security. First, you need a table-valued function that contains some predicate that describes what it the condition that will...

Row-level security enables you to define some predicates that will control who could update rows in the table. First you need to define some table-value function that represents predicate that wll control access policy. CREATE FUNCTION dbo.pUserCanAccessProduct(@CompanyID int) RETURNS TABLE WIT...

Func<int, int> add1 = i => i + 1; Func<int, int, int> add = (i, j) => i + j; // Behaviourally equivalent to: int Add1(int i) { return i + 1; } int Add(int i, int j) { return i + j; } ... Console.WriteLine(add1(42)); //43 Console.WriteLine(Add1(42));...

// assume source is {0, 1, 2, ..., 10} var evens = source.Where(n => n%2 == 0); // evens = {0, 2, 4, ... 10} var strings = source.Select(n => n.ToString()); // strings = {"0", "1", ..., "10"}

The preserveAspectRatio attribute has an optional parameter: meet | slice. The default behavior is meet which stretches the content in both the x and y dimension until it fills either the width or height of the viewBox. The alternative - slice preserves the aspect ratio of the content but scales up ...

Expression<Func<int, bool>> checkEvenExpression = i => i%2 == 0; // lambda expression is automatically converted to an Expression<Func<int, bool>>

Regular expression matching is a powerful tool (in Java, and in other contexts) but it does have some drawbacks. One of these that regular expressions tends to be rather expensive. Pattern and Matcher instances should be reused Consider the following example: /** * Test if all strings in a lis...

The for comprehension is a compact way to run a block of code that depends on the successful result of multiple futures. With f1, f2, f3 three Future[String]'s that will contain the strings one, two, three respectively, val fCombined = for { s1 <- f1 s2 <- f2 ...

In C, there are two unary operators - '++' and '--' that are very common source of confusion. The operator ++ is called the increment operator and the operator -- is called the decrement operator. Both of them can be used used in either prefix form or postfix form. The syntax for prefix form for ++ ...

Errors, when managed properly by the server, will be returned to your client with a specific HTTP status code different from 2xx (see RFC 2616 section 10). It's advised to catch globally your errors from your $.ajaxSetup() as demonstrated in the example below. Therefore all errors coming from your ...

Prepared statements See Prepared statements in MySQLi for how to prepare and execute a query. Binding of results Object-oriented style $stmt->bind_result($forename); Procedural style mysqli_stmt_bind_result($stmt, $forename); The problem with using bind_result is that it requires the s...

You can do neat things via the results of Array "comprehensions"... Like assign multiple variables... from the result of a looping for statement... [express,_] = (require x for x in ['express','underscore']) Or a syntactically sweet version of a "mapped" function call, etc.....

Add the following code to your app.js file: var express = require('express') var morgan = require('morgan') var app = express() app.use(morgan('combined')) app.get('/', function (req, res) { res.send('hello, world!') }) Now when you access your website you will see in the console y...

First, install fs and path in your project npm install --save fs path Add the following code to your app.js file: var express = require('express') var fs = require('fs') var morgan = require('morgan') var path = require('path') var app = express() // create a write stream (in append mo...

First, install fs, file-stream-rotator and path in your project npm install --save fs file-stream-rotator path Add the following code to your app.js file: var FileStreamRotator = require('file-stream-rotator') var express = require('express') var fs = require('fs') var morgan = require('morg...