DeprecationReportBody: lineNumber property

Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The lineNumber read-only property of the DeprecationReportBody interface returns the line in the source file in which the deprecated feature was used.

Note: This property is most useful alongside DeprecationReportBody.sourceFile as it enables the location of the line in that file where the error occurred.


An integer, or null if the line is not known.


In this example we create a new ReportingObserver to observe deprecation reports, then print the value of lineNumber to the console.

let options = {
  types: ["deprecation"],
  buffered: true,

let observer = new ReportingObserver((reports, observer) => {
  let firstReport = reports[0];
  console.log(firstReport.type); // deprecation
  console.log(firstReport.body.sourceFile); // the source file
  console.log(firstReport.body.lineNumber); // the line in that file
}, options);


Deprecation Reporting
# dom-deprecationreportbody-linenumber

Browser compatibility

BCD tables only load in the browser