Built in Objects & Functions - SelfishHellfish/JS_Ref GitHub Wiki

built-in methods and functions that work on the window object/global scope/object.prototype()

timers and intervals

var interval = setInterval(function() {console.log('test');}, 500);
setTimeout(function() {clearInterval(interval);}, 4000)
...will print out 'test' 8 times in 4 seconds.

transforming/parsing formats and values

parseInt() will attempt to transform a string into a number. parseInt('FBB123', 16) will get the integer for the hexadecimal value 'FBB123'
a.toString() will attempt to transform the value stored in a to a string
a.toFixed(2) can be used to round e.g. 10.4 to two decimal places --> 10.40

string functions

strings are treated like arrays
string.length() to get string length, string[index] or string.charAt(index) to access string character, string.concat(' text to append to string'), string.toUpperCase(), string.split(' '), string.trim()` to strip white spaces to the left and right of non-space character boundaries.

math object

Math.PI, Math.E, Math.abs(-5), Math.round(1.4), Math.ceil(1.3) to round up, Math.floor(1.6) to round down, Math.exp(num) == e^num, Math.log(Math.E) == 1, Math.max(1,100,1000) or Math.min(1,100,1000) to get highest/lowest value in list, Math.random()` for random number between 0 and 1

date object

create custom dates with console.log(new Date('2016/05/23').toString()) or print current date with Date.toString()
to get the number of ms since Jan. 1, 1970, do Date.parse('2016/05/23')
Date.getDay for day of week, Date.getDate for day of month

regular expressions

pattern.exec(string)/string.match(pattern) to search expression or pattern.test(string) to evaluate if expression exists, where pattern = /abc/;
cheat sheet