framer-motion
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A simple and powerful JavaScript animation library
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{"version":3,"file":"observers.mjs","sources":["../../../../../src/motion/features/viewport/observers.ts"],"sourcesContent":["type IntersectionHandler = (entry: IntersectionObserverEntry) => void\n\ninterface ElementIntersectionObservers {\n [key: string]: IntersectionObserver\n}\n\n/**\n * Map an IntersectionHandler callback to an element. We only ever make one handler for one\n * element, so even though these handlers might all be triggered by different\n * observers, we can keep them in the same map.\n */\nconst observerCallbacks = new WeakMap<Element, IntersectionHandler>()\n\n/**\n * Multiple observers can be created for multiple element/document roots. Each with\n * different settings. So here we store dictionaries of observers to each root,\n * using serialised settings (threshold/margin) as lookup keys.\n */\nconst observers = new WeakMap<\n Element | Document,\n ElementIntersectionObservers\n>()\n\nconst fireObserverCallback = (entry: IntersectionObserverEntry) => {\n const callback = observerCallbacks.get(entry.target)\n callback && callback(entry)\n}\n\nconst fireAllObserverCallbacks: IntersectionObserverCallback = (entries) => {\n entries.forEach(fireObserverCallback)\n}\n\nfunction initIntersectionObserver({\n root,\n ...options\n}: IntersectionObserverInit): IntersectionObserver {\n const lookupRoot = root || document\n\n /**\n * If we don't have an observer lookup map for this root, create one.\n */\n if (!observers.has(lookupRoot)) {\n observers.set(lookupRoot, {})\n }\n const rootObservers = observers.get(lookupRoot)!\n\n const key = JSON.stringify(options)\n\n /**\n * If we don't have an observer for this combination of root and settings,\n * create one.\n */\n if (!rootObservers[key]) {\n rootObservers[key] = new IntersectionObserver(\n fireAllObserverCallbacks,\n { root, ...options }\n )\n }\n\n return rootObservers[key]\n}\n\nexport function observeIntersection(\n element: Element,\n options: IntersectionObserverInit,\n callback: IntersectionHandler\n) {\n const rootInteresectionObserver = initIntersectionObserver(options)\n\n observerCallbacks.set(element, callback)\n rootInteresectionObserver.observe(element)\n\n return () => {\n observerCallbacks.delete(element)\n rootInteresectionObserver.unobserve(element)\n }\n}\n"],"names":[],"mappings":"AAMA;;;;AAIG;AACH,MAAM,iBAAiB,GAAG,IAAI,OAAO,EAAgC;AAErE;;;;AAIG;AACH,MAAM,SAAS,GAAG,IAAI,OAAO,EAG1B;AAEH,MAAM,oBAAoB,GAAG,CAAC,KAAgC,KAAI;IAC9D,MAAM,QAAQ,GAAG,iBAAiB,CAAC,GAAG,CAAC,KAAK,CAAC,MAAM,CAAC;AACpD,IAAA,QAAQ,IAAI,QAAQ,CAAC,KAAK,CAAC;AAC/B,CAAC;AAED,MAAM,wBAAwB,GAAiC,CAAC,OAAO,KAAI;AACvE,IAAA,OAAO,CAAC,OAAO,CAAC,oBAAoB,CAAC;AACzC,CAAC;AAED,SAAS,wBAAwB,CAAC,EAC9B,IAAI,EACJ,GAAG,OAAO,EACa,EAAA;AACvB,IAAA,MAAM,UAAU,GAAG,IAAI,IAAI,QAAQ;AAEnC;;AAEG;IACH,IAAI,CAAC,SAAS,CAAC,GAAG,CAAC,UAAU,CAAC,EAAE;AAC5B,QAAA,SAAS,CAAC,GAAG,CAAC,UAAU,EAAE,EAAE,CAAC;IACjC;IACA,MAAM,aAAa,GAAG,SAAS,CAAC,GAAG,CAAC,UAAU,CAAE;IAEhD,MAAM,GAAG,GAAG,IAAI,CAAC,SAAS,CAAC,OAAO,CAAC;AAEnC;;;AAGG;AACH,IAAA,IAAI,CAAC,aAAa,CAAC,GAAG,CAAC,EAAE;AACrB,QAAA,aAAa,CAAC,GAAG,CAAC,GAAG,IAAI,oBAAoB,CACzC,wBAAwB,EACxB,EAAE,IAAI,EAAE,GAAG,OAAO,EAAE,CACvB;IACL;AAEA,IAAA,OAAO,aAAa,CAAC,GAAG,CAAC;AAC7B;SAEgB,mBAAmB,CAC/B,OAAgB,EAChB,OAAiC,EACjC,QAA6B,EAAA;AAE7B,IAAA,MAAM,yBAAyB,GAAG,wBAAwB,CAAC,OAAO,CAAC;AAEnE,IAAA,iBAAiB,CAAC,GAAG,CAAC,OAAO,EAAE,QAAQ,CAAC;AACxC,IAAA,yBAAyB,CAAC,OAAO,CAAC,OAAO,CAAC;AAE1C,IAAA,OAAO,MAAK;AACR,QAAA,iBAAiB,CAAC,MAAM,CAAC,OAAO,CAAC;AACjC,QAAA,yBAAyB,CAAC,SAAS,CAAC,OAAO,CAAC;AAChD,IAAA,CAAC;AACL;;;;"}