v-for ke zartacta jerin-jerin abubuwa ta hanyar maimaita gida kan array (ko wani abu/jeri). Kullum ya kamata ka haɗa shi da musamman :key don kaɗai Vue dapat la tafi abubuwa da inganci.
<script setup>
import { ref } from "vue";
const items = ref([{ id: 1, name: "Apple" }, { id: 2, name: "Banana" }]);
</script>
<template>
<ul>
<li v-for="item in items" :key="item.id">{{ item.name }}</li>
</ul>
</template>
<template>
<li v-for="(item, index) in items" :key="item.id">{{ index }}: {{ item.name }}</li>
<li v-for="(value, key) in myObject" :key="key">{{ key }}: {{ value }}</li>
<span v-for="n in 5" :key="n">{{ n }}</span> <!-- range 1..5 -->
</template>
Vue ta yi amfani da key don sanin wane abubuwa suka canza, aka kara, ko an cire, saboda haka za ta iya **amfani da nodi DOM da akwai ta hankali da sake‐tsaida" maimakin gida, maimakin hali. Ba tare da maɓalli mai isasshen jiya ba, Vue ta komo ga "aiki-wuri" dabara wda zai iya haifar da noxe-noxe:
<!-- ❌ using index as key → wrong when the list reorders/filters -->
<li v-for="(item, i) in items" :key="i">
<input /> <!-- input state can attach to the WRONG item after reordering -->
</li>
<!-- ✅ stable unique id → Vue tracks each item correctly -->
<li v-for="item in items" :key="item.id">...</li>
Yi amfani da index array a matsayin maɓalli gida-gida ne - lokacin da abubuwa aka sake tsada, aka kada waje, ko aka janye, jiha / DOM-ƙa gida (kamar ƙimar sakon a cikin kaɗi) zai iya a tsaida ko a janye daban-daban jeri.
<!-- ❌ avoid — ambiguous precedence -->
<li v-for="x in items" v-if="x.active">...</li>
<!-- ✅ filter in a computed, or wrap with <template v-for> -->
v-for hanya take nuni-nunia jerin-jerin mai tasiri ne.
:key ba aike ne a aikace-aikace gida: durable, musamman maɓalli zai ba da damar Vue ɗin jerin aiki da inganci kuma zai gudana juriyar haɗin jihi mai tsanani a sake-tsada/tacewa.
Sanin amfani da tutunkira ID tunani (ba tare da index ga jerin-jerin mai tasiri ba) kuma ajiye v-for/v-if baje baje shine mahallin aiki gida, ingantacciyar jerin-jerin.
Ɗakin karatu na tambayoyin hira na IT tare da amsoshi cikakke — daga Junior zuwa Senior.
Ba da Gudummawa