{"version":3,"file":"onFCP.js","sources":["../../../../src/metrics/web-vitals/onFCP.ts"],"sourcesContent":["/*\n * Copyright 2020 Google LLC\n *\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n *     https://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n */\n\nimport { bindReporter } from './lib/bindReporter';\nimport { getActivationStart } from './lib/getActivationStart';\nimport { getVisibilityWatcher } from './lib/getVisibilityWatcher';\nimport { initMetric } from './lib/initMetric';\nimport { observe } from './lib/observe';\nimport { whenActivated } from './lib/whenActivated';\nimport type { FCPMetric, MetricRatingThresholds, ReportOpts } from './types';\n\n/** Thresholds for FCP. See https://web.dev/articles/fcp#what_is_a_good_fcp_score */\nexport const FCPThresholds: MetricRatingThresholds = [1800, 3000];\n\n/**\n * Calculates the [FCP](https://web.dev/articles/fcp) value for the current page and\n * calls the `callback` function once the value is ready, along with the\n * relevant `paint` performance entry used to determine the value. The reported\n * value is a `DOMHighResTimeStamp`.\n */\nexport const onFCP = (onReport: (metric: FCPMetric) => void, opts: ReportOpts = {}) => {\n  whenActivated(() => {\n    const visibilityWatcher = getVisibilityWatcher();\n    const metric = initMetric('FCP');\n    let report: ReturnType<typeof bindReporter>;\n\n    const handleEntries = (entries: FCPMetric['entries']) => {\n      for (const entry of entries) {\n        if (entry.name === 'first-contentful-paint') {\n          po!.disconnect();\n\n          // Only report if the page wasn't hidden prior to the first paint.\n          if (entry.startTime < visibilityWatcher.firstHiddenTime) {\n            // The activationStart reference is used because FCP should be\n            // relative to page activation rather than navigation start if the\n            // page was prerendered. But in cases where `activationStart` occurs\n            // after the FCP, this time should be clamped at 0.\n            metric.value = Math.max(entry.startTime - getActivationStart(), 0);\n            metric.entries.push(entry);\n            report(true);\n          }\n        }\n      }\n    };\n\n    const po = observe('paint', handleEntries);\n\n    if (po) {\n      report = bindReporter(onReport, metric, FCPThresholds, opts.reportAllChanges);\n    }\n  });\n};\n"],"names":["whenActivated","getVisibilityWatcher","initMetric","getActivationStart","observe","bindReporter"],"mappings":";;;;;;;;;AAyBO,MAAM,aAAA,GAAwC,CAAC,IAAA,EAAM,GAAI;AAQzD,MAAM,KAAA,GAAQ,CAAC,QAAA,EAAuC,IAAA,GAAmB,EAAC,KAAM;AACrF,EAAAA,2BAAA,CAAc,MAAM;AAClB,IAAA,MAAM,oBAAoBC,yCAAA,EAAqB;AAC/C,IAAA,MAAM,MAAA,GAASC,sBAAW,KAAK,CAAA;AAC/B,IAAA,IAAI,MAAA;AAEJ,IAAA,MAAM,aAAA,GAAgB,CAAC,OAAA,KAAkC;AACvD,MAAA,KAAA,MAAW,SAAS,OAAA,EAAS;AAC3B,QAAA,IAAI,KAAA,CAAM,SAAS,wBAAA,EAA0B;AAC3C,UAAA,EAAA,CAAI,UAAA,EAAW;AAGf,UAAA,IAAI,KAAA,CAAM,SAAA,GAAY,iBAAA,CAAkB,eAAA,EAAiB;AAKvD,YAAA,MAAA,CAAO,QAAQ,IAAA,CAAK,GAAA,CAAI,MAAM,SAAA,GAAYC,qCAAA,IAAsB,CAAC,CAAA;AACjE,YAAA,MAAA,CAAO,OAAA,CAAQ,KAAK,KAAK,CAAA;AACzB,YAAA,MAAA,CAAO,IAAI,CAAA;AAAA,UACb;AAAA,QACF;AAAA,MACF;AAAA,IACF,CAAA;AAEA,IAAA,MAAM,EAAA,GAAKC,eAAA,CAAQ,OAAA,EAAS,aAAa,CAAA;AAEzC,IAAA,IAAI,EAAA,EAAI;AACN,MAAA,MAAA,GAASC,yBAAA,CAAa,QAAA,EAAU,MAAA,EAAQ,aAAA,EAAe,KAAK,gBAAgB,CAAA;AAAA,IAC9E;AAAA,EACF,CAAC,CAAA;AACH;;;;;"}