Most programming languages have several types of numeric data, but JavaScript gets away with just one.
All numbers are and are stored as doubles.
See also': Javascript - Integer
var myVariable = 10;
var myVariable = +10;
var myVariable = Number(10);
let MAX_INT = 4294967295; // Math.pow(2,32) - 1;
Number.MAX_SAFE_INTEGER // 2^53 - 1
Number.MIN_SAFE_INTEGER // (-(2^53 - 1)).
Number.MAX_VALUE; // 2^1024
Number.MIN_VALUE; // 0
There is no integer in a javascript.
var myNumber = 0.1 + 0.2
console.log("myNumber is not 0.3 but " + myNumber)
To convert values to numbers explicitly, you can use:
Example:
console.log(typeof(+"3"))
The arithmetic operators -, *, /, and % all attempt to coerce their arguments to numbers before doing their calculation.
The operator + is subtler, because it is overloaded to perform either numeric addition or string concatenation, depending on the types of its arguments.
Silent coercions can also hide errors because it will prevent errors or failure in an arithmetic calculation
Variable value | Number Value |
---|---|
null | 0 |
true | 1 |
false | 0 |
Non-Number String | NaN |
Empty String | 0 |
Number String | The number represented |
Object without the valueOf property | NaN |
Object with the valueOf property | The return value of the valueOf function |
Empty Array | 0 |
Non Empty Array with one number value | The first number |
Non Empty Array with more than one value | NaN |
undefined | NaN |
NaN | NaN |
function | NaN |
Proof:
x = [
null,
true,
false,
"Non-Empty String",
"",
"1",
{ toString: function() { return "Object without valueof"; } },
{ toString: function() { return "Object with valueOf"; } , valueOf: function() { return 10; } },
undefined,
[],
[ 1 ],
[ 1, 2 ],
NaN,
function(){}
];
function numberCoerced(value) {
this.value = value;
this.coercedValue = Number(value);
this.valueType = typeof(value);
}
numbers = [];
for (i in x) {
numbers.push(new numberCoerced(x[i]));
}
console.table(numbers);
The bitwise arithmetic operators|bitwise arithmetic operators don't operate on their arguments directly as floating-point numbers, they implicitly convert them to 32-bit integers.
Most operators works on integer and real number (float)
function operationArithmetic(desc,opString){
this.descripion = desc;
this.operation = opString;
this.outcome = eval(opString);
}
var ops = [
["Multiplication","0.1 * 1.9"],
["Addition", "-99 + 100"],
["Minus", "21 - 12.3"],
["Division","2.5 / 5"],
["Modulo", "21 % 8"]
];
opsTable = [];
for (i in ops) {
opsTable.push(new operationArithmetic(ops[i][0],ops[i][1]));
}
console.table(opsTable);
console.log('"10" + 1 ='); // Concat
console.log("10" + 1); // Concat
console.log('1 + "10" = '); // Concat
console.log(1 + "10"); // Concat
console.log('1 + 2 + "10" performs an addition, then a concatenation giving the below result:');
console.log(1 + 2 + "10"); // Addition + Concat
console.log('true + "10" = '); // Concat
console.log(true + "10"); // Concat
console.log('1 + true = ');
console.log(1 + true); // True is coerced to 1
console.log("10" - 1); // Arithmetic Operation
console.log(10 - "1"); // Arithmetic Operation
console.log( (8).toString(2) ); // 8 in base 2 (binary)
// 1000
// Exactly 00000000000000000000000000001000 in 32 bit but the 0 at the left are not shown.
where:
console.log("The number 1001 in base 2 has the representation ("+parseInt("1001", 2 )+") in base 10")
// 1001 is a base 2 (binary) number representation
function numberRepresentation(decimal, binary, hexadecimal) {
this.decimal = decimal;
this.binary = binary;
this.hexadecimal = hexadecimal;
}
numbers =[]
for (var i=0;i<=16;i++) {
numbers.push(
new numberRepresentation(
i,
i.toString(2),
i.toString(16).toUpperCase()
)
);
}
console.table(numbers);