on 16-May-2018 (Wed)

Intuitively speaking, a neighbourhood of a point is a set of points containing that point where one can move some amount away from that point without leaving the set.

In mathematics, an integral equation is an equation in which an unknown function appears under an integral sign.

The most basic type of integral equation is where φ is an unknown function,  f  is a known function, and K is another known function of two variables, often called the kernel function.

It is worth noting that integral equations often do not have an analytical solution, and must be solved numerically.

TypeScript is JavaScript with optional typing. TypeScript is a compiled language, it’s not interpreted at run-time. The TypeScript compiler takes TypeScript files (.ts) and compiles them in to JavaScript files (.js).

TypeScript can be installed through the NPM package manager.

npm install -g typescript

The -g means it’s installed on your system globally so that the TypeScript compiler can be used in any of your projects.

You can use the tsc command in several different ways. Here’s a couple of helpful common usages.

You can also compile all your TypeScript files down to a single JavaScript file. This can reduce the number of HTTP requests a browser has to make and improve performance on HTTP 1.x sites. To do this use the --out option like so:

tsc *.ts --out app.js

When there’s a variable or an argument in a function or method call, you can annotate your code with types. To annotate, follow the variable or argument with a colon and followed by it’s type.

var myName: string = "Andrew"; function printName(name: string) { console.log(name);
}

In this code we want every object pushed in to the addressBook array to conform to the Contact interface. When this is compiled to JavaScript this disappears, but this is helpful in development.

interface Contact { name: string, email: string, phone: string
} var addressBook: Contact[] = [];