{
  "javascript": {
    "builtins": {
      "WeakMap": {
        "__compat": {
          "mdn_url": "https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/WeakMap",
          "spec_url": "https://tc39.es/ecma262/#sec-weakmap-objects",
          "support": {
            "chrome": {
              "version_added": "36"
            },
            "chrome_android": {
              "version_added": "36"
            },
            "edge": {
              "version_added": "12"
            },
            "firefox": {
              "version_added": "6"
            },
            "firefox_android": {
              "version_added": "6"
            },
            "ie": {
              "version_added": "11"
            },
            "nodejs": [
              {
                "version_added": "0.12"
              },
              {
                "version_added": "0.10",
                "flags": [
                  {
                    "type": "runtime_flag",
                    "name": "--harmony"
                  }
                ]
              }
            ],
            "opera": {
              "version_added": "23"
            },
            "opera_android": {
              "version_added": "24"
            },
            "safari": {
              "version_added": "8"
            },
            "safari_ios": {
              "version_added": "8"
            },
            "samsunginternet_android": {
              "version_added": "3.0"
            },
            "webview_android": {
              "version_added": "37"
            }
          },
          "status": {
            "experimental": false,
            "standard_track": true,
            "deprecated": false
          }
        },
        "WeakMap": {
          "__compat": {
            "description": "<code>WeakMap()</code> constructor",
            "mdn_url": "https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/WeakMap/WeakMap",
            "spec_url": "https://tc39.es/ecma262/#sec-weakmap-constructor",
            "support": {
              "chrome": {
                "version_added": "36"
              },
              "chrome_android": {
                "version_added": "36"
              },
              "edge": {
                "version_added": "12"
              },
              "firefox": {
                "version_added": "6"
              },
              "firefox_android": {
                "version_added": "6"
              },
              "ie": {
                "version_added": "11"
              },
              "nodejs": [
                {
                  "version_added": "0.12"
                },
                {
                  "version_added": "0.10",
                  "flags": [
                    {
                      "type": "runtime_flag",
                      "name": "--harmony"
                    }
                  ]
                }
              ],
              "opera": {
                "version_added": "23"
              },
              "opera_android": {
                "version_added": "24"
              },
              "safari": {
                "version_added": "8"
              },
              "safari_ios": {
                "version_added": "8"
              },
              "samsunginternet_android": {
                "version_added": "3.0"
              },
              "webview_android": {
                "version_added": "37"
              }
            },
            "status": {
              "experimental": false,
              "standard_track": true,
              "deprecated": false
            }
          },
          "iterable_allowed": {
            "__compat": {
              "description": "<code>new WeakMap(iterable)</code>",
              "support": {
                "chrome": {
                  "version_added": "38"
                },
                "chrome_android": {
                  "version_added": "38"
                },
                "edge": {
                  "version_added": "12"
                },
                "firefox": {
                  "version_added": "36"
                },
                "firefox_android": {
                  "version_added": "36"
                },
                "ie": {
                  "version_added": false
                },
                "nodejs": {
                  "version_added": "0.12"
                },
                "opera": {
                  "version_added": "25"
                },
                "opera_android": {
                  "version_added": "25"
                },
                "safari": {
                  "version_added": "9"
                },
                "safari_ios": {
                  "version_added": "9"
                },
                "samsunginternet_android": {
                  "version_added": "3.0"
                },
                "webview_android": {
                  "version_added": "38"
                }
              },
              "status": {
                "experimental": false,
                "standard_track": true,
                "deprecated": false
              }
            }
          },
          "new_required": {
            "__compat": {
              "description": "<code>WeakMap()</code> without <code>new</code> throws",
              "support": {
                "chrome": {
                  "version_added": "36"
                },
                "chrome_android": {
                  "version_added": "36"
                },
                "edge": {
                  "version_added": "12"
                },
                "firefox": {
                  "version_added": "42"
                },
                "firefox_android": {
                  "version_added": "42"
                },
                "ie": {
                  "version_added": "11"
                },
                "nodejs": {
                  "version_added": "0.12"
                },
                "opera": {
                  "version_added": "23"
                },
                "opera_android": {
                  "version_added": "24"
                },
                "safari": {
                  "version_added": "9"
                },
                "safari_ios": {
                  "version_added": "9"
                },
                "samsunginternet_android": {
                  "version_added": "3.0"
                },
                "webview_android": {
                  "version_added": "37"
                }
              },
              "status": {
                "experimental": false,
                "standard_track": true,
                "deprecated": false
              }
            }
          },
          "null_allowed": {
            "__compat": {
              "description": "<code>new WeakMap(null)</code>",
              "support": {
                "chrome": {
                  "version_added": "36"
                },
                "chrome_android": {
                  "version_added": "36"
                },
                "edge": {
                  "version_added": "12"
                },
                "firefox": {
                  "version_added": "37"
                },
                "firefox_android": {
                  "version_added": "37"
                },
                "ie": {
                  "version_added": "11"
                },
                "nodejs": [
                  {
                    "version_added": "0.12"
                  },
                  {
                    "version_added": "0.10",
                    "flags": [
                      {
                        "type": "runtime_flag",
                        "name": "--harmony"
                      }
                    ]
                  }
                ],
                "opera": {
                  "version_added": "23"
                },
                "opera_android": {
                  "version_added": "24"
                },
                "safari": {
                  "version_added": "8"
                },
                "safari_ios": {
                  "version_added": "8"
                },
                "samsunginternet_android": {
                  "version_added": "3.0"
                },
                "webview_android": {
                  "version_added": "37"
                }
              },
              "status": {
                "experimental": false,
                "standard_track": true,
                "deprecated": false
              }
            }
          }
        },
        "clear": {
          "__compat": {
            "mdn_url": "https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/WeakMap/clear",
            "support": {
              "chrome": {
                "version_added": "36",
                "version_removed": "43"
              },
              "chrome_android": {
                "version_added": "36",
                "version_removed": "43"
              },
              "edge": {
                "version_added": false
              },
              "firefox": {
                "version_added": "20",
                "version_removed": "46"
              },
              "firefox_android": {
                "version_added": "20",
                "version_removed": "46"
              },
              "ie": {
                "version_added": "11"
              },
              "nodejs": {
                "version_added": "0.12",
                "version_removed": "4.0.0"
              },
              "opera": {
                "version_added": "25",
                "version_removed": "30"
              },
              "opera_android": {
                "version_added": "25",
                "version_removed": "30"
              },
              "safari": {
                "version_added": "8",
                "version_removed": "9"
              },
              "safari_ios": {
                "version_added": "8",
                "version_removed": "9"
              },
              "samsunginternet_android": {
                "version_added": "3.0",
                "version_removed": "4.0"
              },
              "webview_android": {
                "version_added": "37",
                "version_removed": "43"
              }
            },
            "status": {
              "experimental": false,
              "standard_track": false,
              "deprecated": true
            }
          }
        },
        "delete": {
          "__compat": {
            "mdn_url": "https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/WeakMap/delete",
            "spec_url": "https://tc39.es/ecma262/#sec-weakmap.prototype.delete",
            "support": {
              "chrome": {
                "version_added": "36"
              },
              "chrome_android": {
                "version_added": "36"
              },
              "edge": {
                "version_added": "12"
              },
              "firefox": {
                "version_added": "6",
                "notes": "Prior to Firefox 38, this method threw a <code>TypeError</code> when the key parameter was not an object. This has been fixed in version 38 and later to return <code>false</code> as per the ES2015 standard."
              },
              "firefox_android": {
                "version_added": "6",
                "notes": "Prior to Firefox 38, this method threw a <code>TypeError</code> when the key parameter was not an object. This has been fixed in version 38 and later to return <code>false</code> as per the ES2015 standard."
              },
              "ie": {
                "version_added": "11"
              },
              "nodejs": [
                {
                  "version_added": "0.12"
                },
                {
                  "version_added": "0.10",
                  "flags": [
                    {
                      "type": "runtime_flag",
                      "name": "--harmony"
                    }
                  ]
                }
              ],
              "opera": {
                "version_added": "23"
              },
              "opera_android": {
                "version_added": "24"
              },
              "safari": {
                "version_added": "8"
              },
              "safari_ios": {
                "version_added": "8"
              },
              "samsunginternet_android": {
                "version_added": "3.0"
              },
              "webview_android": {
                "version_added": "37"
              }
            },
            "status": {
              "experimental": false,
              "standard_track": true,
              "deprecated": false
            }
          }
        },
        "get": {
          "__compat": {
            "mdn_url": "https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/WeakMap/get",
            "spec_url": "https://tc39.es/ecma262/#sec-weakmap.prototype.get",
            "support": {
              "chrome": {
                "version_added": "36"
              },
              "chrome_android": {
                "version_added": "36"
              },
              "edge": {
                "version_added": "12"
              },
              "firefox": {
                "version_added": "6",
                "notes": "Prior to Firefox 38, this method threw a <code>TypeError</code> when the key parameter was not an object. However, the ES2015 specification specifies to return <code>undefined</code> instead. Furthermore, <code>WeakMap.prototype.get</code> accepted an optional second argument as a fallback value, which is not part of the standard. Both non-standard behaviors are removed in version 38 and higher."
              },
              "firefox_android": {
                "version_added": "6",
                "notes": "Prior to Firefox 38, this method threw a <code>TypeError</code> when the key parameter was not an object. However, the ES2015 specification specifies to return <code>undefined</code> instead. Furthermore, <code>WeakMap.prototype.get</code> accepted an optional second argument as a fallback value, which is not part of the standard. Both non-standard behaviors are removed in version 38 and higher."
              },
              "ie": {
                "version_added": "11"
              },
              "nodejs": [
                {
                  "version_added": "0.12"
                },
                {
                  "version_added": "0.10",
                  "flags": [
                    {
                      "type": "runtime_flag",
                      "name": "--harmony"
                    }
                  ]
                }
              ],
              "opera": {
                "version_added": "23"
              },
              "opera_android": {
                "version_added": "24"
              },
              "safari": {
                "version_added": "8"
              },
              "safari_ios": {
                "version_added": "8"
              },
              "samsunginternet_android": {
                "version_added": "3.0"
              },
              "webview_android": {
                "version_added": "37"
              }
            },
            "status": {
              "experimental": false,
              "standard_track": true,
              "deprecated": false
            }
          }
        },
        "has": {
          "__compat": {
            "mdn_url": "https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/WeakMap/has",
            "spec_url": "https://tc39.es/ecma262/#sec-weakmap.prototype.has",
            "support": {
              "chrome": {
                "version_added": "36"
              },
              "chrome_android": {
                "version_added": "36"
              },
              "edge": {
                "version_added": "12"
              },
              "firefox": {
                "version_added": "6",
                "notes": "Prior to Firefox 38, this method threw a <code>TypeError</code> when the key parameter was not an object. This has been fixed in version 38 and later to return <code>false</code> as per the ES2015 standard."
              },
              "firefox_android": {
                "version_added": "6",
                "notes": "Prior to Firefox 38, this method threw a <code>TypeError</code> when the key parameter was not an object. This has been fixed in version 38 and later to return <code>false</code> as per the ES2015 standard."
              },
              "ie": {
                "version_added": "11"
              },
              "nodejs": [
                {
                  "version_added": "0.12"
                },
                {
                  "version_added": "0.10",
                  "flags": [
                    {
                      "type": "runtime_flag",
                      "name": "--harmony"
                    }
                  ]
                }
              ],
              "opera": {
                "version_added": "23"
              },
              "opera_android": {
                "version_added": "24"
              },
              "safari": {
                "version_added": "8"
              },
              "safari_ios": {
                "version_added": "8"
              },
              "samsunginternet_android": {
                "version_added": "3.0"
              },
              "webview_android": {
                "version_added": "37"
              }
            },
            "status": {
              "experimental": false,
              "standard_track": true,
              "deprecated": false
            }
          }
        },
        "set": {
          "__compat": {
            "mdn_url": "https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/WeakMap/set",
            "spec_url": "https://tc39.es/ecma262/#sec-weakmap.prototype.set",
            "support": {
              "chrome": {
                "version_added": "36"
              },
              "chrome_android": {
                "version_added": "36"
              },
              "edge": {
                "version_added": "12"
              },
              "firefox": {
                "version_added": "6",
                "notes": "Prior to Firefox 38, this method threw a <code>TypeError</code> when the key parameter was not an object. This has been fixed in version 38 and later to return <code>false</code> as per the ES2015 standard."
              },
              "firefox_android": {
                "version_added": "6",
                "notes": "Prior to Firefox 38, this method threw a <code>TypeError</code> when the key parameter was not an object. This has been fixed in version 38 and later to return <code>false</code> as per the ES2015 standard."
              },
              "ie": {
                "version_added": "11",
                "partial_implementation": true,
                "notes": "Returns 'undefined' instead of the 'Map' object."
              },
              "nodejs": [
                {
                  "version_added": "0.12"
                },
                {
                  "version_added": "0.10",
                  "flags": [
                    {
                      "type": "runtime_flag",
                      "name": "--harmony"
                    }
                  ]
                }
              ],
              "opera": {
                "version_added": "23"
              },
              "opera_android": {
                "version_added": "24"
              },
              "safari": {
                "version_added": "8"
              },
              "safari_ios": {
                "version_added": "8"
              },
              "samsunginternet_android": {
                "version_added": "3.0"
              },
              "webview_android": {
                "version_added": "37"
              }
            },
            "status": {
              "experimental": false,
              "standard_track": true,
              "deprecated": false
            }
          }
        }
      }
    }
  }
}