affix.vue
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<template>
<div>
<div :class="classes" :style="styles">
<slot></slot>
</div>
</div>
</template>
<script>
const prefixCls = 'ivu-affix';
function getScroll(target, top) {
const prop = top ? 'pageYOffset' : 'pageXOffset';
const method = top ? 'scrollTop' : 'scrollLeft';
let ret = target[prop];
if (typeof ret !== 'number') {
ret = window.document.documentElement[method];
}
return ret;
}
function getOffset(element) {
const rect = element.getBoundingClientRect();
const scrollTop = getScroll(window, true);
const scrollLeft = getScroll(window);
const docEl = window.document.body;
const clientTop = docEl.clientTop || 0;
const clientLeft = docEl.clientLeft || 0;
return {
top: rect.top + scrollTop - clientTop,
left: rect.left + scrollLeft - clientLeft
}
}
export default {
props: {
offsetTop: {
type: Number,
default: 0
},
offsetBottom: {
type: Number
}
},
data () {
return {
affix: false,
styles: {}
}
},
computed: {
offsetType () {
let type = 'top';
if (this.offsetBottom >= 0) {
type = 'bottom';
}
return type;
},
classes () {
return [
{
[`${prefixCls}`]: this.affix
}
]
}
},
ready () {
window.addEventListener('scroll', this.handleScroll, false);
window.addEventListener('resize', this.handleScroll, false);
},
beforeDestroy () {
window.removeEventListener('scroll', this.handleScroll, false);
window.removeEventListener('resize', this.handleScroll, false);
},
methods: {
handleScroll () {
const affix = this.affix;
const scrollTop = getScroll(window, true);
const elOffset = getOffset(this.$el);
const windowHeight = window.innerHeight;
const elHeight = this.$el.getElementsByTagName('div')[0].offsetHeight;
// Fixed Top
if ((elOffset.top - this.offsetTop) < scrollTop && this.offsetType == 'top' && !affix) {
this.affix = true;
this.styles = {
top: `${this.offsetTop}px`,
left: `${elOffset.left}px`,
width: `${this.$el.offsetWidth}px`
};
this.$emit('on-change', true);
} else if ((elOffset.top - this.offsetTop) > scrollTop && this.offsetType == 'top' && affix) {
this.affix = false;
this.styles = null;
this.$emit('on-change', false);
}
// Fixed Bottom
if ((elOffset.top + this.offsetBottom + elHeight) > (scrollTop + windowHeight) && this.offsetType == 'bottom' && !affix) {
this.affix = true;
this.styles = {
bottom: `${this.offsetBottom}px`,
left: `${elOffset.left}px`,
width: `${this.$el.offsetWidth}px`
};
this.$emit('on-change', true);
} else if ((elOffset.top + this.offsetBottom + elHeight) < (scrollTop + windowHeight) && this.offsetType == 'bottom' && affix) {
this.affix = false;
this.styles = null;
this.$emit('on-change', false);
}
}
}
}
</script>