Simple lint based on TS compiler API

lint-demo.ts

import * as ts from 'typescript'; // don't forget to "npm install typescript -g && npm link typescript"

var codeToAnalyse = `
function f1() {}
var x = 10;
function hello() { function hmm() {} }
`;

var source = ts.createSourceFile("test.ts", codeToAnalyse, ts.ScriptTarget.ES5);

analyse(source);

function analyse(node: ts.Node)
{
    if (node.kind == ts.SyntaxKind.FunctionDeclaration)
    {
        var name = (<ts.FunctionDeclaration>node).name.text;
        if (name.length < 5)
        {
            console.warn("Function name " + name + " is too short. Provide a better name please!");
        }
    }
    ts.forEachChild(node, analyse);
}

// output:
// Function name f1 is too short. Provide a better name please!
// Function name hmm is too short. Provide a better name please!