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---
title: "RangeError: repeat count must be non-negative"
slug: Web/JavaScript/Reference/Errors/Negative_repetition_count
page-type: javascript-error
---
{{jsSidebar("Errors")}}
The JavaScript exception "repeat count must be non-negative" occurs when the
{{jsxref("String.prototype.repeat()")}} method is used with a `count`
argument that is a negative number.
## Message
```plain
RangeError: Invalid count value: -1 (V8-based)
RangeError: repeat count must be non-negative (Firefox)
RangeError: String.prototype.repeat argument must be greater than or equal to 0 and not be Infinity (Safari)
```
## Error type
{{jsxref("RangeError")}}
## What went wrong?
The {{jsxref("String.prototype.repeat()")}} method has been used. It has a
`count` parameter indicating the number of times to repeat the string. It
must be between 0 and less than positive {{jsxref("Infinity")}} and cannot be a negative
number. The range of allowed values can be described like this: \[0, +∞).
## Examples
### Invalid cases
```js example-bad
"abc".repeat(-1); // RangeError
```
### Valid cases
```js example-good
"abc".repeat(0); // ''
"abc".repeat(1); // 'abc'
"abc".repeat(2); // 'abcabc'
"abc".repeat(3.5); // 'abcabcabc' (count will be converted to integer)
```
## See also
- {{jsxref("String.prototype.repeat()")}}