The toJSON()
method is a serializer; it returns a JSON representation of the performance entry
object.
Note: This feature is available in Web Workers.
Syntax
json = perfEntry.toJSON();
Arguments
- None
Return value
- json
- A JSON object that is the serialization of the
PerformanceEntry
object.
Example
The following example shows the use of the toJSON()
method.
function run_PerformanceEntry() { log("PerformanceEntry support ..."); if (performance.mark === undefined) { log("... performance.mark Not supported"); return; } // Create some performance entries via the mark() method performance.mark("Begin"); do_work(50000); performance.mark("End"); // Use getEntries() to iterate through the each entry var p = performance.getEntries(); for (var i=0; i < p.length; i++) { log("Entry[" + i + "]"); check_PerformanceEntry(p[i]); } } function check_PerformanceEntry(obj) { var properties = ["name", "entryType", "startTime", "duration"]; var methods = ["toJSON"]; for (var i=0; i < properties.length; i++) { // check each property var supported = properties[i] in obj; if (supported) log("..." + properties[i] + " = " + obj[properties[i]]); else log("..." + properties[i] + " = Not supported"); } for (var i=0; i < methods.length; i++) { // check each method var supported = typeof obj[methods[i]] == "function"; if (supported) { var js = obj[methods[i]](); log("..." + methods[i] + "() = " + JSON.stringify(js)); } else { log("..." + methods[i] + " = Not supported"); } } }
Specifications
Specification | Status | Comment |
---|---|---|
Performance Timeline Level 2 The definition of 'toJSON' in that specification. |
Candidate Recommendation | Initial definition of toJSON() method. |
Browser compatibility
The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
toJSON | Chrome Full support Yes | Edge Full support 16 | Firefox Full support Yes | IE No support No | Opera Full support Yes | Safari Full support 11 | WebView Android Full support Yes | Chrome Android Full support Yes | Firefox Android Full support 25 | Opera Android Full support Yes | Safari iOS Full support 11 | Samsung Internet Android Full support Yes |
Legend
- Full support
- Full support
- No support
- No support