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String API: string.repeat(count)

Appends count copies of string to each other and returns it.

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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


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