[PWA] 14. Loop cursor
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import idb from ‘idb‘; var dbPromise = idb.open(‘test-db‘, 4, function (upgradeDb) { switch (upgradeDb.oldVersion) { case 0: // keyval store is already created at version 1 var keyValStore = upgradeDb.createObjectStore(‘keyval‘); keyValStore.put("world", "hello"); case 1: // new version upgradeDb.createObjectStore(‘people‘, {keyPath: ‘name‘}); case 2: var peopleStore = upgradeDb.transaction.objectStore(‘people‘); peopleStore.createIndex(‘animal‘, ‘favoriteAnimal‘); case 3: var peopleStore = upgradeDb.transaction.objectStore(‘people‘); peopleStore.createIndex(‘age‘, ‘age‘); } }); // read "hello" in "keyval" dbPromise.then(function (db) { var tx = db.transaction(‘keyval‘); // Open a transaction var keyValStore = tx.objectStore(‘keyval‘); // read the store return keyValStore.get(‘hello‘); // get value by key }).then(function (val) { console.log(‘The value of "hello" is:‘, val); }); dbPromise.then(function (db) { var tx = db.transaction(‘people‘, ‘readwrite‘); var peopleStore = tx.objectStore(‘people‘); peopleStore.put({ name: "John", // name is the key age: 23, favoriteAnimal: ‘cat‘ }); peopleStore.put({ name: "Joe", // name is the key age: 21, favoriteAnimal: ‘cat‘ }); peopleStore.put({ name: "Jie", // name is the key age: 22, favoriteAnimal: ‘dog‘ }); peopleStore.put({ name: "Jay", // name is the key age: 24, favoriteAnimal: ‘dog‘ }); return tx.complete; }).then(function () { console.log("People are added"); }); dbPromise.then(function (db) { var tx = db.transaction(‘people‘, ‘readwrite‘); var peopleStore = tx.objectStore(‘people‘); var ageIndex = peopleStore.index(‘age‘); return ageIndex.openCursor(); }).then(function (cursor) { if (!cursor) return; return cursor.advance(1); // skip the first person }).then(function logPerson(cursor) { if(cursor.value.name == "Jie"){ cursor.delete(); // delete } if(cursor.value.name == "Jay"){ console.log("Cursor at:", cursor.value.name); var joe = cursor.value; joe.favoriteAnimal = "Bird"; cursor.update(joe); // update } return cursor.continue().then(logPerson); }).then(function () { console.log("DONE"); });
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