hands on vue - 부모의 손자에게 바로 다이렉트로 값 보내기(provide&inject)

[목표]

1. props와 emit를 연달아 사용하여 자식의 자식의 자식... 에게

함수 혹은 데이터를 보내지 않고 다이렉트로 보내는 방법에 대해 익숙해져 보자

---

원래는 이런식으로 보낸다

 

하지만 provide & inject를 사용하면 다음 그림과 같다

---

수정 전과 후의 소스를 비교하여 연습하자

 

[수정전 - App.vue]

<template>
  <div>
    <active-element
      :topic-title="activeTopic && activeTopic.title"
      :text="activeTopic && activeTopic.fullText"
    ></active-element>
    <knowledge-base :topics="topics" @select-topic="activateTopic"></knowledge-base>
  </div>
</template>

<script>
export default {
  data() {
    return {
      topics: [
        {
          id: 'basics',
          title: 'The Basics',
          description: 'Core Vue basics you have to know',
          fullText:
            'Vue is a great framework and it has a couple of key concepts: Data binding, events, components and reactivity - that should tell you something!',
        },
        {
          id: 'components',
          title: 'Components',
          description:
            'Components are a core concept for building Vue UIs and apps',
          fullText:
            'With components, you can split logic (and markup) into separate building blocks and then combine those building blocks (and re-use them) to build powerful user interfaces.',
        },
      ],
      activeTopic: null,
    };
  },
  methods: {
    activateTopic(topicId) {
      this.activeTopic = this.topics.find((topic) => topic.id === topicId);
    },
  },
};
</script>

<style>
* {
  box-sizing: border-box;
}
html {
  font-family: sans-serif;
}
body {
  margin: 0;
}
section {
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.26);
  margin: 2rem auto;
  max-width: 40rem;
  padding: 1rem;
  border-radius: 12px;
}

ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  justify-content: center;
}

li {
  border-radius: 12px;
  border: 1px solid #ccc;
  padding: 1rem;
  width: 15rem;
  margin: 0 1rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

h2 {
  margin: 0.75rem 0;
  text-align: center;
}

button {
  font: inherit;
  border: 1px solid #c70053;
  background-color: #c70053;
  color: white;
  padding: 0.75rem 2rem;
  border-radius: 30px;
  cursor: pointer;
}

button:hover,
button:active {
  background-color: #e24d8b;
  border-color: #e24d8b;
}
</style>

[수정전 KnowledgeBase.vue]

<template>
  <section>
    <h2>Select a Topic</h2>
    <knowledge-grid :topics="topics" @select-topic="$emit('select-topic', $event)"></knowledge-grid>
  </section>
</template>

<script>
export default {
  props: ['topics'],
  emits: ['select-topic'],
};
</script>

[수정전 KnowledgeGrid.vue]

<template>
  <ul>
    <knowledge-element
      v-for="topic in topics"
      :key="topic.id"
      :id="topic.id"
      :topic-name="topic.title"
      :description="topic.description"
      @select-topic="$emit('select-topic', $event)"
    ></knowledge-element>
  </ul>
</template>

<script>
export default {
  props: ['topics'],
  emits: ['select-topic']
};
</script>

[수정전 KnowledgeElement.vue]

<template>
  <li>
    <h3>{{ topicName }}</h3>
    <p>{{ description }}</p>
    <button @click="$emit('select-topic', id)">Learn More</button>
  </li>
</template>

<script>
export default {
  props: ['id', 'topicName', 'description'],
  emits: ['select-topic'],
};
</script>

[수정전 ActiveElement.vue]

<template>
  <section>
    <h2>{{ topicTitle }}</h2>
    <p>{{ text }}</p>
  </section>
</template>

<script>
export default {
  props: ['topicTitle', 'text'],
};
</script>

[수정전 main.js]

import { createApp } from 'vue';

import App from './App.vue';
import ActiveElement from './components/ActiveElement.vue';
import KnowledgeBase from './components/KnowledgeBase.vue';
import KnowledgeElement from './components/KnowledgeElement.vue';
import KnowledgeGrid from './components/KnowledgeGrid.vue';

const app = createApp(App);

app.component('active-element', ActiveElement);
app.component('knowledge-base', KnowledgeBase);
app.component('knowledge-element', KnowledgeElement);
app.component('knowledge-grid', KnowledgeGrid);

app.mount('#app');

---

[수정후 - App.vue]

<template>
  <div>
    <active-element
      :topic-title="activeTopic && activeTopic.title"
      :text="activeTopic && activeTopic.fullText"
    ></active-element>
    <knowledge-base></knowledge-base>
  </div>
</template>

<script>
export default {
  data() {
    return {
      topics: [
        {
          id: 'basics',
          title: 'The Basics',
          description: 'Core Vue basics you have to know',
          fullText:
            'Vue is a great framework and it has a couple of key concepts: Data binding, events, components and reactivity - that should tell you something!',
        },
        {
          id: 'components',
          title: 'Components',
          description:
            'Components are a core concept for building Vue UIs and apps',
          fullText:
            'With components, you can split logic (and markup) into separate building blocks and then combine those building blocks (and re-use them) to build powerful user interfaces.',
        },
      ],
      activeTopic: null,
    };
  },
  methods: {
    activateTopic(topicId) {
      this.activeTopic = this.topics.find((topic) => topic.id === topicId);
    },
  },
  provide(){
    return{
      topics: this.topics,
      selectTopic: this.activateTopic,
    }
  }
};
</script>

<style>
* {
  box-sizing: border-box;
}
html {
  font-family: sans-serif;
}
body {
  margin: 0;
}
section {
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.26);
  margin: 2rem auto;
  max-width: 40rem;
  padding: 1rem;
  border-radius: 12px;
}

ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  justify-content: center;
}

li {
  border-radius: 12px;
  border: 1px solid #ccc;
  padding: 1rem;
  width: 15rem;
  margin: 0 1rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

h2 {
  margin: 0.75rem 0;
  text-align: center;
}

button {
  font: inherit;
  border: 1px solid #c70053;
  background-color: #c70053;
  color: white;
  padding: 0.75rem 2rem;
  border-radius: 30px;
  cursor: pointer;
}

button:hover,
button:active {
  background-color: #e24d8b;
  border-color: #e24d8b;
}
</style>

[수정후 KnowledgeBase.vue]

<template>
  <section>
    <h2>Select a Topic</h2>
    <knowledge-grid ></knowledge-grid>
  </section>
</template>

<script>
export default {
};
</script>

[수정후 KnowledgeGrid.vue]

<template>
  <ul>
    <knowledge-element
      v-for="topic in topics"
      :key="topic.id"
      :id="topic.id"
      :topic-name="topic.title"
      :description="topic.description"
    ></knowledge-element>
  </ul>
</template>

<script>
export default {
  inject: ['topics'],
  mounted(){
    alert(this.topics);
  }
};
</script>

[수정후 KnowledgeElement.vue]

<template>
  <li>
    <h3>{{ topicName }}</h3>
    <p>{{ description }}</p>
    <button @click="selectTopic(id)">Learn More</button>
  </li>
</template>

<script>
export default {
  inject: ['selectTopic'],
  props: ['id', 'topicName', 'description'],
};
</script>

[수정후 ActiveElement.vue]

<template>
  <section>
    <h2>{{ topicTitle }}</h2>
    <p>{{ text }}</p>
  </section>
</template>

<script>
export default {
  props: ['topicTitle', 'text'],
};
</script>