Nuxt•4d ago

Fake Ref

Hey, I have code like this:

watch(tableStatus, (newStatus) => {
    if (newStatus === "success") {
        MAP_COLUMNS = tableData.value.columns
        for (const property in MAP_COLUMNS) {
            VALID_ORDER_BY[property] = property
            MAP_COLUMNS[property].filter_value = ref("")
            console.log("Object:", MAP_COLUMNS[property])
            console.log("Is ref?", isRef(MAP_COLUMNS[property].filter_value))
        }
  }
})

watch(tableStatus, (newStatus) => {
    if (newStatus === "success") {
        MAP_COLUMNS = tableData.value.columns
        for (const property in MAP_COLUMNS) {
            VALID_ORDER_BY[property] = property
            MAP_COLUMNS[property].filter_value = ref("")
            console.log("Object:", MAP_COLUMNS[property])
            console.log("Is ref?", isRef(MAP_COLUMNS[property].filter_value))
        }
  }
})

and I’m getting something like this in the console - why isn’t filter_value a ref? And how can I create a ref on‑the‑fly inside a for loop?

2 Replies

kapa.ai•4d ago

Hi @FoxCode. I'm kapa.ai, your friendly support bot. I will try to answer your question by searching through the knowledge base. :wave: ---------------------- The issue you're encountering is related to Vue's reactivity system and how refs work in Nuxt/Vue 3. Let me explain what's happening and how to fix it. Why filter_value isn't a ref When you're creating a ref inside an object property like this:

MAP_COLUMNS[property].filter_value = ref("")

MAP_COLUMNS[property].filter_value = ref("")

You're actually losing the reactivity because you're assigning the ref to a property of a non-reactive object. This is a common issue in Vue 3 when working with refs. According to the Vue documentation, you should not destructure props or assign refs to object properties directly, as this will cause them to lose their reactivity: Stack Overflow: Vue3 / Nuxt3 - how to use props directly in setup How to fix it There are a few approaches to solve this: 1. Use toRef or toRefs for object properties

watch(tableStatus, (newStatus) => {
    if (newStatus === "success") {
        MAP_COLUMNS = tableData.value.columns
        for (const property in MAP_COLUMNS) {
            VALID_ORDER_BY[property] = property
            // Create a ref that maintains reactivity
            MAP_COLUMNS[property].filter_value = ref("")
            // Make the object property itself reactive
            MAP_COLUMNS[property] = reactive(MAP_COLUMNS[property])
        }
    }
})

watch(tableStatus, (newStatus) => {
    if (newStatus === "success") {
        MAP_COLUMNS = tableData.value.columns
        for (const property in MAP_COLUMNS) {
            VALID_ORDER_BY[property] = property
            // Create a ref that maintains reactivity
            MAP_COLUMNS[property].filter_value = ref("")
            // Make the object property itself reactive
            MAP_COLUMNS[property] = reactive(MAP_COLUMNS[property])
        }
    }
})

2. Create a reactive object from the start A better approach would be to make your entire MAP_COLUMNS object reactive from the beginning:

watch(tableStatus, (newStatus) => {
    if (newStatus === "success") {
        MAP_COLUMNS = reactive(tableData.value.columns)
        for (const property in MAP_COLUMNS) {
            VALID_ORDER_BY[property] = property
            MAP_COLUMNS[property].filter_value = ""  // No need for ref here
        }
    }
})

watch(tableStatus, (newStatus) => {
    if (newStatus === "success") {
        MAP_COLUMNS = reactive(tableData.value.columns)
        for (const property in MAP_COLUMNS) {
            VALID_ORDER_BY[property] = property
            MAP_COLUMNS[property].filter_value = ""  // No need for ref here
        }
    }
})

3. Use computed properties for dynamic refs If you specifically need refs for each filter value, you could use a separate object to store them:

const filterValues = reactive({})

watch(tableStatus, (newStatus) => {
    if (newStatus === "success") {
        MAP_COLUMNS = tableData.value.columns
        for (const property in MAP_COLUMNS) {
            VALID_ORDER_BY[property] = property
            filterValues[property] = ref("")
            // Link the filter_value to the ref
            MAP_COLUMNS[property].filter_value = filterValues[property]
        }
    }
})

const filterValues = reactive({})

watch(tableStatus, (newStatus) => {
    if (newStatus === "success") {
        MAP_COLUMNS = tableData.value.columns
        for (const property in MAP_COLUMNS) {
            VALID_ORDER_BY[property] = property
            filterValues[property] = ref("")
            // Link the filter_value to the ref
            MAP_COLUMNS[property].filter_value = filterValues[property]
        }
    }
})

Important note about auto-imports In Nuxt, ref is auto-imported, but it's important to understand that refs need to be used correctly to maintain reactivity. When working with refs in loops or assigning them to object properties, you need to be careful about how Vue's reactivity system works. Nuxt Docs: Auto-imports Remember that when watching refs, you should watch the ref itself, not its .value property: Stack Overflow: Vue.js two-way data binding with deep properties This is a common issue in Vue 3's reactivity system, and understanding how refs work is crucial for building reactive applications in Nuxt. ---------------------- Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: ----------------------

kapa.ai•4d ago

<@363971301947342848> Kapa.ai is still learning and improving, please let me know how I did by reacting below.

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