String API: string.repeat(count)

str.repeat(x) concatenates x copies of str and returns it

the 1st parameter the count

• if missing, returns an empty string
• when 1, the string stays the same
• for 3 the string x becomes xxx
• for 0 an empty string is returned

the count is not a number

• such as a string "3", it gets converted to an int
• a hex looking number as a string "0xA", it gets converted to an int
• and does not look like a number, it behaves like 0

throws an error for

• a count of <0
• a count of +Infinty

accepts everything that can be coerced to a string

• e.g. a boolean
• e.g. a number

for my own (string) class

• calls toString() to make it a string
• toString() is only called once

Links

spec The official specification, actually quite good to read for this function.
spec The part in the spec, which explains the conversion of a string to a number.
mdn docs The Mozilla Developer Network docs, contains good examples.
announcement Announcement of this kata on twitter.