You are on the editable version of MDN Web Docs

View as an MDN Web Docs user: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error/toSource

Non-standard
This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.

The toSource() method returns code that could eval to the same error.

Syntax

e.toSource()

Return value

A string containing the source code of the error.

Examples

Using toSource

Calling the toSource method of an Error instance (including NativeErrors) will return a string containing the source code of the error. This string can be evaluated to create an (approximately) equal object. Naturally, the string containing the source follows the structure of the Error constructor. For example:

(newname(message ,fileName,lineNumber))

where these attributes correspond to the respective properties of the error instance.

Note: Be aware that the properties used by the toSource method in the creation of this string are mutable and may not accurately reflect the function used to create an error instance or the filename or line number where the actual error occurred.

Specifications

Not part of any standard.

Browser compatibility

Update compatibility data on GitHub
DesktopMobileServer
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung InternetNode.js
toSource
Non-standard
Chrome No support NoEdge No support NoFirefox No support 1 — 74
Notes
No support 1 — 74
Notes
Notes Starting in Firefox 74, toSource() is no longer available for use by web content. It is still allowed for internal and privileged code.
IE No support NoOpera No support NoSafari No support NoWebView Android No support NoChrome Android No support NoFirefox Android Full support 4Opera Android No support NoSafari iOS No support NoSamsung Internet Android No support Nonodejs No support No

Legend

Full support  
Full support
No support  
No support
Non-standard. Expect poor cross-browser support.
Non-standard. Expect poor cross-browser support.
See implementation notes.
See implementation notes.

See also

Document Tags and Contributors

Last updated by: mfuji09,