{
  "javascript": {
    "classes": {
      "__compat": {
        "mdn_url": "https://developer.mozilla.org/docs/Web/JavaScript/Reference/Classes",
        "spec_url": "https://tc39.es/ecma262/multipage/ecmascript-language-functions-and-classes.html#sec-class-definitions",
        "tags": [
          "web-features:class-syntax",
          "web-features:snapshot:ecmascript-2015"
        ],
        "support": {
          "chrome": [
            {
              "version_added": "49"
            },
            {
              "version_added": "42",
              "version_removed": "49",
              "notes": "Strict mode is required."
            }
          ],
          "chrome_android": "mirror",
          "deno": {
            "version_added": "1.0"
          },
          "edge": {
            "version_added": "13"
          },
          "firefox": {
            "version_added": "45"
          },
          "firefox_android": "mirror",
          "ie": {
            "version_added": false
          },
          "nodejs": {
            "version_added": "6.0.0"
          },
          "oculus": "mirror",
          "opera": "mirror",
          "opera_android": "mirror",
          "safari": {
            "version_added": "9"
          },
          "safari_ios": "mirror",
          "samsunginternet_android": "mirror",
          "webview_android": "mirror",
          "webview_ios": "mirror"
        },
        "status": {
          "experimental": false,
          "standard_track": true,
          "deprecated": false
        }
      },
      "constructor": {
        "__compat": {
          "mdn_url": "https://developer.mozilla.org/docs/Web/JavaScript/Reference/Classes/constructor",
          "spec_url": "https://tc39.es/ecma262/multipage/ecmascript-language-functions-and-classes.html#sec-static-semantics-constructormethod",
          "tags": [
            "web-features:class-syntax",
            "web-features:snapshot:ecmascript-2015"
          ],
          "support": {
            "chrome": [
              {
                "version_added": "49"
              },
              {
                "version_added": "42",
                "version_removed": "49",
                "notes": "Strict mode is required."
              }
            ],
            "chrome_android": "mirror",
            "deno": {
              "version_added": "1.0"
            },
            "edge": {
              "version_added": "13"
            },
            "firefox": {
              "version_added": "45"
            },
            "firefox_android": "mirror",
            "ie": {
              "version_added": false
            },
            "nodejs": {
              "version_added": "6.0.0"
            },
            "oculus": "mirror",
            "opera": "mirror",
            "opera_android": "mirror",
            "safari": {
              "version_added": "9"
            },
            "safari_ios": "mirror",
            "samsunginternet_android": "mirror",
            "webview_android": "mirror",
            "webview_ios": "mirror"
          },
          "status": {
            "experimental": false,
            "standard_track": true,
            "deprecated": false
          }
        }
      },
      "extends": {
        "__compat": {
          "mdn_url": "https://developer.mozilla.org/docs/Web/JavaScript/Reference/Classes/extends",
          "spec_url": "https://tc39.es/ecma262/multipage/ecmascript-language-functions-and-classes.html#sec-class-definitions",
          "tags": [
            "web-features:class-syntax",
            "web-features:snapshot:ecmascript-2015"
          ],
          "support": {
            "chrome": [
              {
                "version_added": "49"
              },
              {
                "version_added": "42",
                "version_removed": "49",
                "notes": "Strict mode is required."
              }
            ],
            "chrome_android": "mirror",
            "deno": {
              "version_added": "1.0"
            },
            "edge": {
              "version_added": "13"
            },
            "firefox": {
              "version_added": "45"
            },
            "firefox_android": "mirror",
            "ie": {
              "version_added": false
            },
            "nodejs": {
              "version_added": "6.0.0"
            },
            "oculus": "mirror",
            "opera": "mirror",
            "opera_android": "mirror",
            "safari": {
              "version_added": "9"
            },
            "safari_ios": "mirror",
            "samsunginternet_android": "mirror",
            "webview_android": "mirror",
            "webview_ios": "mirror"
          },
          "status": {
            "experimental": false,
            "standard_track": true,
            "deprecated": false
          }
        }
      },
      "private_class_fields": {
        "__compat": {
          "description": "Private class fields",
          "mdn_url": "https://developer.mozilla.org/docs/Web/JavaScript/Reference/Classes/Private_properties",
          "spec_url": "https://tc39.es/ecma262/multipage/ecmascript-language-lexical-grammar.html#prod-PrivateIdentifier",
          "tags": [
            "web-features:class-syntax"
          ],
          "support": {
            "chrome": {
              "version_added": "74"
            },
            "chrome_android": "mirror",
            "deno": {
              "version_added": "1.0"
            },
            "edge": "mirror",
            "firefox": {
              "version_added": "90"
            },
            "firefox_android": "mirror",
            "ie": {
              "version_added": false
            },
            "nodejs": {
              "version_added": "12.0.0"
            },
            "oculus": "mirror",
            "opera": "mirror",
            "opera_android": "mirror",
            "safari": {
              "version_added": "14.1"
            },
            "safari_ios": "mirror",
            "samsunginternet_android": "mirror",
            "webview_android": "mirror",
            "webview_ios": "mirror"
          },
          "status": {
            "experimental": false,
            "standard_track": true,
            "deprecated": false
          }
        }
      },
      "private_class_fields_in": {
        "__compat": {
          "description": "Private class fields 'in'",
          "mdn_url": "https://developer.mozilla.org/docs/Web/JavaScript/Reference/Classes/Private_properties",
          "spec_url": "https://tc39.es/ecma262/multipage/ecmascript-language-expressions.html#prod-00OK517S",
          "tags": [
            "web-features:class-syntax"
          ],
          "support": {
            "chrome": {
              "version_added": "91"
            },
            "chrome_android": "mirror",
            "deno": {
              "version_added": "1.9"
            },
            "edge": "mirror",
            "firefox": {
              "version_added": "90"
            },
            "firefox_android": "mirror",
            "ie": {
              "version_added": false
            },
            "nodejs": {
              "version_added": "16.4.0"
            },
            "oculus": "mirror",
            "opera": "mirror",
            "opera_android": "mirror",
            "safari": {
              "version_added": "15"
            },
            "safari_ios": "mirror",
            "samsunginternet_android": "mirror",
            "webview_android": "mirror",
            "webview_ios": "mirror"
          },
          "status": {
            "experimental": false,
            "standard_track": true,
            "deprecated": false
          }
        }
      },
      "private_class_methods": {
        "__compat": {
          "description": "Private class methods",
          "mdn_url": "https://developer.mozilla.org/docs/Web/JavaScript/Reference/Classes/Private_properties",
          "spec_url": "https://tc39.es/ecma262/multipage/ecmascript-language-lexical-grammar.html#prod-PrivateIdentifier",
          "tags": [
            "web-features:class-syntax"
          ],
          "support": {
            "chrome": {
              "version_added": "84"
            },
            "chrome_android": "mirror",
            "deno": {
              "version_added": "1.0"
            },
            "edge": "mirror",
            "firefox": {
              "version_added": "90"
            },
            "firefox_android": "mirror",
            "ie": {
              "version_added": false
            },
            "nodejs": {
              "version_added": "14.6.0"
            },
            "oculus": "mirror",
            "opera": "mirror",
            "opera_android": "mirror",
            "safari": {
              "version_added": "15"
            },
            "safari_ios": "mirror",
            "samsunginternet_android": "mirror",
            "webview_android": "mirror",
            "webview_ios": "mirror"
          },
          "status": {
            "experimental": false,
            "standard_track": true,
            "deprecated": false
          }
        }
      },
      "public_class_fields": {
        "__compat": {
          "description": "Public class fields",
          "mdn_url": "https://developer.mozilla.org/docs/Web/JavaScript/Reference/Classes/Public_class_fields",
          "spec_url": "https://tc39.es/ecma262/multipage/ecmascript-language-functions-and-classes.html#prod-FieldDefinition",
          "tags": [
            "web-features:class-syntax"
          ],
          "support": {
            "chrome": {
              "version_added": "72"
            },
            "chrome_android": "mirror",
            "deno": {
              "version_added": "1.0"
            },
            "edge": "mirror",
            "firefox": {
              "version_added": "69"
            },
            "firefox_android": "mirror",
            "ie": {
              "version_added": false
            },
            "nodejs": {
              "version_added": "12.0.0"
            },
            "oculus": "mirror",
            "opera": "mirror",
            "opera_android": "mirror",
            "safari": [
              {
                "version_added": "16"
              },
              {
                "version_added": "14.1",
                "version_removed": "16",
                "partial_implementation": true,
                "notes": "Parentheses in field initializers can lead to `ReferenceError`s. See [bug 236843](https://webkit.org/b/236843)."
              },
              {
                "version_added": "14",
                "version_removed": "14.1",
                "partial_implementation": true,
                "notes": "Doesn't support public static fields. See [bug 194095](https://webkit.org/b/194095)."
              }
            ],
            "safari_ios": "mirror",
            "samsunginternet_android": "mirror",
            "webview_android": "mirror",
            "webview_ios": "mirror"
          },
          "status": {
            "experimental": false,
            "standard_track": true,
            "deprecated": false
          }
        }
      },
      "static": {
        "__compat": {
          "mdn_url": "https://developer.mozilla.org/docs/Web/JavaScript/Reference/Classes/static",
          "spec_url": "https://tc39.es/ecma262/multipage/ecmascript-language-functions-and-classes.html#sec-class-definitions",
          "tags": [
            "web-features:class-syntax",
            "web-features:snapshot:ecmascript-2015"
          ],
          "support": {
            "chrome": [
              {
                "version_added": "49"
              },
              {
                "version_added": "42",
                "version_removed": "49",
                "notes": "Strict mode is required."
              }
            ],
            "chrome_android": "mirror",
            "deno": {
              "version_added": "1.0"
            },
            "edge": {
              "version_added": "13"
            },
            "firefox": {
              "version_added": "45"
            },
            "firefox_android": "mirror",
            "ie": {
              "version_added": false
            },
            "nodejs": {
              "version_added": "6.0.0"
            },
            "oculus": "mirror",
            "opera": "mirror",
            "opera_android": "mirror",
            "safari": {
              "version_added": "9"
            },
            "safari_ios": "mirror",
            "samsunginternet_android": "mirror",
            "webview_android": "mirror",
            "webview_ios": "mirror"
          },
          "status": {
            "experimental": false,
            "standard_track": true,
            "deprecated": false
          }
        }
      },
      "static_class_fields": {
        "__compat": {
          "description": "Static class fields",
          "mdn_url": "https://developer.mozilla.org/docs/Web/JavaScript/Reference/Classes/Public_class_fields",
          "spec_url": "https://tc39.es/ecma262/multipage/ecmascript-language-functions-and-classes.html#prod-FieldDefinition",
          "tags": [
            "web-features:class-syntax"
          ],
          "support": {
            "chrome": {
              "version_added": "72"
            },
            "chrome_android": "mirror",
            "deno": {
              "version_added": "1.0"
            },
            "edge": "mirror",
            "firefox": {
              "version_added": "75"
            },
            "firefox_android": "mirror",
            "ie": {
              "version_added": false
            },
            "nodejs": {
              "version_added": "12.0.0"
            },
            "oculus": "mirror",
            "opera": "mirror",
            "opera_android": "mirror",
            "safari": {
              "version_added": "14.1"
            },
            "safari_ios": "mirror",
            "samsunginternet_android": "mirror",
            "webview_android": "mirror",
            "webview_ios": "mirror"
          },
          "status": {
            "experimental": false,
            "standard_track": true,
            "deprecated": false
          }
        }
      },
      "static_initialization_blocks": {
        "__compat": {
          "description": "Class static initialization blocks",
          "mdn_url": "https://developer.mozilla.org/docs/Web/JavaScript/Reference/Classes/Static_initialization_blocks",
          "spec_url": "https://tc39.es/ecma262/multipage/ecmascript-language-functions-and-classes.html#prod-ClassStaticBlock",
          "tags": [
            "web-features:class-syntax"
          ],
          "support": {
            "chrome": {
              "version_added": "94"
            },
            "chrome_android": "mirror",
            "deno": {
              "version_added": "1.14"
            },
            "edge": "mirror",
            "firefox": {
              "version_added": "93"
            },
            "firefox_android": "mirror",
            "ie": {
              "version_added": false
            },
            "nodejs": {
              "version_added": "16.11.0"
            },
            "oculus": "mirror",
            "opera": "mirror",
            "opera_android": "mirror",
            "safari": {
              "version_added": "16.4"
            },
            "safari_ios": "mirror",
            "samsunginternet_android": "mirror",
            "webview_android": "mirror",
            "webview_ios": "mirror"
          },
          "status": {
            "experimental": false,
            "standard_track": true,
            "deprecated": false
          }
        }
      }
    }
  }
}