A set of examples that remind me how Boolean coercion works in JavaScript

JsBooleanCoercion.js

var truthTest = function(value){
  return value ? "true" : "false";
}

// Boolean literals behave as expected
var trueLiteral = true;
var falseLiteral = false;
truthTest(trueLiteral);  // true
truthTest(falseLiteral); // false

// null and undefined are always coerced to false
var nullLiteral = null;
var undefinedVariable;
truthTest(nullLiteral); // false
truthTest(undefinedVariable); // false

// strings are coreced to false if their length is zero or if the string itself
// is a representation of false (in any casing), true otherwise
var emptyString = '';
var nonEmptyString = 'hello';
var stringRepresentationOfFalse = 'FaLsE';
truthTest(emptyString);               // false
truthTest(nonEmptyString);            // true
truthTest(stringReprestationOfFalse); // false

// numbers are coerced to false if zero or NaN, true otherwise
var zero = 0;
var NaNLiteral = NaN;
var nonZeroNumber = 5;
truthTest(zero);          // false
truthTest(NaNLiteral);    // false
truthTest(nonZeroNumber); // true

// objects (including arrays) are coerced to true
var emptyObj = {};
var nonEmptyObj = { x: 1 };
var emptyArray = [];
truthTest(emptyObj);      // true
truthTest(nonEmptyObj);   // true
truthTest(emptyArray);    // true