From be01f0b4bb9522b44a34a4bc020ac029f6f864f1 Mon Sep 17 00:00:00 2001
From: Sergio Crisostomo <sergiosbox@gmail.com>
Date: Wed, 27 Sep 2017 14:46:42 +0200
Subject: [PATCH] New component: Scroll

---
 .eslintrc.json                              |   3 +-
 package-lock.json                           |   7 +-
 package.json                                |   1 +
 src/components/scroll/index.js              |   3 +
 src/components/scroll/loading-component.vue |  39 +++
 src/components/scroll/scroll.vue            | 271 ++++++++++++++++++++
 src/index.js                                |  14 +-
 src/styles/components/index.less            |   3 +-
 src/styles/components/scroll.less           |  67 +++++
 9 files changed, 399 insertions(+), 9 deletions(-)
 create mode 100644 src/components/scroll/index.js
 create mode 100644 src/components/scroll/loading-component.vue
 create mode 100644 src/components/scroll/scroll.vue
 create mode 100644 src/styles/components/scroll.less

diff --git a/.eslintrc.json b/.eslintrc.json
index 46c3cbe3..3bc3fd34 100644
--- a/.eslintrc.json
+++ b/.eslintrc.json
@@ -8,7 +8,8 @@
         "sourceType": "module"
     },
     "env": {
-        "browser": true
+        "browser": true,
+        "es6": true
     },
     "extends": "eslint:recommended",
     "plugins": ["vue"],
diff --git a/package-lock.json b/package-lock.json
index 05039016..f410f167 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "iview",
-  "version": "2.3.2",
+  "version": "2.4.0",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
@@ -12493,6 +12493,11 @@
         "lodash.escape": "3.2.0"
       }
     },
+    "lodash.throttle": {
+      "version": "4.1.1",
+      "resolved": "https://registry.npmjs.org/lodash.throttle/-/lodash.throttle-4.1.1.tgz",
+      "integrity": "sha1-wj6RtxAkKscMN/HhzaknTMOb8vQ="
+    },
     "lodash.uniq": {
       "version": "4.5.0",
       "resolved": "https://registry.npmjs.org/lodash.uniq/-/lodash.uniq-4.5.0.tgz",
diff --git a/package.json b/package.json
index 8f489201..d82aba6b 100644
--- a/package.json
+++ b/package.json
@@ -44,6 +44,7 @@
     "core-js": "^2.5.0",
     "deepmerge": "^1.5.1",
     "element-resize-detector": "^1.1.12",
+    "lodash.throttle": "^4.1.1",
     "popper.js": "^0.6.4",
     "tinycolor2": "^1.4.1"
   },
diff --git a/src/components/scroll/index.js b/src/components/scroll/index.js
new file mode 100644
index 00000000..dedbe686
--- /dev/null
+++ b/src/components/scroll/index.js
@@ -0,0 +1,3 @@
+import Scroll from './scroll.vue';
+
+export default Scroll;
diff --git a/src/components/scroll/loading-component.vue b/src/components/scroll/loading-component.vue
new file mode 100644
index 00000000..f4a214ad
--- /dev/null
+++ b/src/components/scroll/loading-component.vue
@@ -0,0 +1,39 @@
+
+<template lang="html">
+    <div :class="wrapperClasses">
+        <div :class="spinnerClasses">
+            <Spin fix>
+                <Icon type="load-c" size="18" :class="iconClasses"></Icon>
+                <div v-if="text" :class="textClasses">{{text}}</div>
+            </Spin>
+
+        </div>
+    </div>
+</template>
+
+<script>
+const prefixCls = 'ivu-scroll';
+
+export default {
+    props: ['text', 'active', 'spinnerHeight'],
+    computed: {
+        wrapperClasses() {
+            return [
+                `${prefixCls}-loader-wrapper`,
+                {
+                    [`${prefixCls}-loader-wrapper-active`]: this.active
+                }
+            ];
+        },
+        spinnerClasses() {
+            return `${prefixCls}-spinner`;
+        },
+        iconClasses() {
+            return `${prefixCls}-spinner-icon`;
+        },
+        textClasses() {
+            return `${prefixCls}-loader-text`;
+        }
+    }
+};
+</script>
diff --git a/src/components/scroll/scroll.vue b/src/components/scroll/scroll.vue
new file mode 100644
index 00000000..9933da32
--- /dev/null
+++ b/src/components/scroll/scroll.vue
@@ -0,0 +1,271 @@
+
+<template>
+    <div :class="wrapClasses" style="touch-action: none;">
+        <div
+            :class="scrollContainerClasses"
+            @scroll="handleScroll"
+            @wheel="onWheel"
+            @touchstart="onPointerDown"
+            ref="scrollContainer"
+        >
+            <div :class="loaderClasses" :style="{paddingTop: wrapperPadding.paddingTop}" ref="toploader">
+                <loader :text="loadingText" :active="showTopLoader"></loader>
+            </div>
+            <div :class="slotContainerClasses" ref="scrollContent">
+                <slot></slot>
+            </div>
+            <div :class="loaderClasses" :style="{paddingBottom: wrapperPadding.paddingBottom}" ref="bottomLoader">
+                <loader :text="loadingText" :active="showBottomLoader"></loader>
+            </div>
+        </div>
+    </div>
+</template>
+<script>
+    import throttle from 'lodash.throttle';
+    import loader from './loading-component.vue';
+
+    const prefixCls = 'ivu-scroll';
+    const dragConfig = {
+        sensitivity: 10,
+        minimumStartDragOffset: 5, // minimum start drag offset
+    };
+
+    export default {
+        name: 'Scroll',
+        mixins: [],
+        components: {loader},
+        props: {
+            onReachTop: {
+                type: Function,
+                default: () => Promise.resolve()
+            },
+            onReachBottom: {
+                type: Function,
+                default: () => Promise.resolve()
+            },
+            onReachEdge: {
+                type: Function,
+                default: () => Promise.resolve()
+            },
+            loadingText: {
+                type: String,
+                default: ''
+            }
+        },
+        data() {
+            return {
+                showTopLoader: false,
+                showBottomLoader: false,
+                showBodyLoader: false,
+                lastScroll: 0,
+                reachedTopScrollLimit: true,
+                reachedBottomScrollLimit: false,
+                topRubberPadding: 0,
+                bottomRubberPadding: 0,
+                rubberRollBackTimeout: false,
+                isLoading: false,
+                pointerTouchDown: null,
+                touchScroll: false,
+                handleScroll: () => {},
+                pointerUpHandler: () => {},
+                pointerMoveHandler: () => {},
+            };
+        },
+        computed: {
+            wrapClasses() {
+                return `${prefixCls}-wrapper`;
+            },
+            scrollContainerClasses() {
+                return `${prefixCls}-container`;
+            },
+            slotContainerClasses() {
+                return [
+                    `${prefixCls}-content`,
+                    {
+                        [`${prefixCls}-content-loading`]: this.showBodyLoader
+                    }
+                ];
+            },
+            loaderClasses() {
+                return `${prefixCls}-loader`;
+            },
+            wrapperPadding() {
+                return {
+                    paddingTop: this.topRubberPadding + 'px',
+                    paddingBottom: this.bottomRubberPadding + 'px'
+                };
+            }
+        },
+        methods: {
+            // just to improve feeling of loading and avoid scroll trailing events fired by the browser
+            waitOneSecond() {
+                return new Promise(resolve => {
+                    setTimeout(resolve, 2000);
+                });
+            },
+
+            onCallback(dir) {
+                this.isLoading = true;
+                this.showBodyLoader = true;
+                if (dir > 0) {
+                    this.showTopLoader = true;
+                    this.topRubberPadding = 20;
+                } else {
+                    this.showBottomLoader = true;
+                    this.bottomRubberPadding = 20;
+
+                    // to force the scroll to the bottom while height is animating
+                    let bottomLoaderHeight = 0;
+                    const container = this.$refs.scrollContainer;
+                    const initialScrollTop = container.scrollTop;
+                    for (var i = 0; i < 20; i++) {
+                        setTimeout(() => {
+                            bottomLoaderHeight = Math.max(
+                                bottomLoaderHeight,
+                                this.$refs.bottomLoader.getBoundingClientRect().height
+                            );
+                            container.scrollTop = initialScrollTop + bottomLoaderHeight;
+                        }, i * 50);
+                    }
+                }
+
+                const callbacks = [this.waitOneSecond(), this.onReachEdge(dir)];
+                callbacks.push(dir > 0 ? this.onReachTop() : this.onReachBottom());
+
+                let tooSlow = setTimeout(() => {
+                    this.reset();
+                }, 5000);
+
+                Promise.all(callbacks).then(() => {
+                    clearTimeout(tooSlow);
+                    this.reset();
+                });
+            },
+
+            reset() {
+                [
+                    'showTopLoader',
+                    'showBottomLoader',
+                    'showBodyLoader',
+                    'isLoading',
+                    'reachedTopScrollLimit',
+                    'reachedBottomScrollLimit'
+                ].forEach(prop => (this[prop] = false));
+
+                this.lastScroll = 0;
+                this.topRubberPadding = 0;
+                this.bottomRubberPadding = 0;
+                clearInterval(this.rubberRollBackTimeout);
+
+                // if we remove the handler too soon the screen will bump
+                if (this.touchScroll) {
+                    setTimeout(() => {
+                        window.removeEventListener('touchend', this.pointerUpHandler);
+                        this.$refs.scrollContainer.removeEventListener('touchmove', this.pointerMoveHandler);
+                        this.touchScroll = false;
+                    }, 500);
+                }
+            },
+
+            onWheel() {
+                if (this.isLoading) return;
+
+                // get the wheel direction
+                const wheelDelta = event.wheelDelta ? event.wheelDelta : -(event.detail || event.deltaY);
+                this.stretchEdge(wheelDelta);
+            },
+
+            stretchEdge(direction) {
+                clearTimeout(this.rubberRollBackTimeout);
+
+                // if the scroll is not strong enough, lets reset it
+                this.rubberRollBackTimeout = setTimeout(() => {
+                    if (!this.isLoading) this.reset();
+                }, 250);
+
+                // to give the feeling its ruberish and can be puled more to start loading
+                if (direction > 0 && this.reachedTopScrollLimit) {
+                    this.topRubberPadding += 5 - this.topRubberPadding / 5;
+                    if (this.topRubberPadding > 20) this.onCallback(1);
+                } else if (direction < 0 && this.reachedBottomScrollLimit) {
+                    this.bottomRubberPadding += 6 - this.bottomRubberPadding / 4;
+                    if (this.bottomRubberPadding > 20) this.onCallback(-1);
+                } else {
+                    this.onScroll();
+                }
+            },
+
+            onScroll() {
+                if (this.isLoading) return;
+                const el = this.$refs.scrollContainer;
+                const scrollDirection = Math.sign(this.lastScroll - el.scrollTop); // IE has no Math.sign, check that webpack polyfills this
+                const displacement = el.scrollHeight - el.clientHeight - el.scrollTop;
+
+                if (scrollDirection == -1 && displacement <= dragConfig.sensitivity) {
+                    this.reachedBottomScrollLimit = true;
+                } else if (scrollDirection >= 0 && el.scrollTop == 0) {
+                    this.reachedTopScrollLimit = true;
+                } else {
+                    this.reachedTopScrollLimit = false;
+                    this.reachedBottomScrollLimit = false;
+                    this.lastScroll = el.scrollTop;
+                }
+            },
+
+            getTouchCoordinates(e) {
+                return {
+                    x: e.touches[0].pageX,
+                    y: e.touches[0].pageY
+                };
+            },
+
+            onPointerDown(e) {
+                // we just use scroll and wheel in desktop, no mousedown
+                if (this.isLoading) return;
+                if (e.type == 'touchstart') {
+                    // if we start do touchmove on the scroll edger the browser will scroll the body
+                    // by adding 5px margin on pointer down we avoid this behaviour and the scroll/touchmove
+                    // in the component will not be exported outside of the component
+                    const container = this.$refs.scrollContainer;
+                    if (this.reachedTopScrollLimit) container.scrollTop = 5;
+                    else if (this.reachedBottomScrollLimit) container.scrollTop -= 5;
+                }
+                if (e.type == 'touchstart' && this.$refs.scrollContainer.scrollTop == 0)
+                    this.$refs.scrollContainer.scrollTop = 5;
+
+                this.pointerTouchDown = this.getTouchCoordinates(e);
+                window.addEventListener('touchend', this.pointerUpHandler);
+                this.$refs.scrollContainer.parentElement.addEventListener('touchmove', e => {
+                    e.stopPropagation();
+                    this.pointerMoveHandler(e);
+                }, {passive: false, useCapture: true});
+            },
+
+            onPointerMove(e) {
+                if (!this.pointerTouchDown) return;
+                if (this.isLoading) return;
+
+                const pointerPosition = this.getTouchCoordinates(e);
+                const yDiff = pointerPosition.y - this.pointerTouchDown.y;
+
+                this.stretchEdge(yDiff);
+
+                if (!this.touchScroll) {
+                    const wasDragged = Math.abs(yDiff) > dragConfig.minimumStartDragOffset;
+                    if (wasDragged) this.touchScroll = true;
+                    else return;
+                }
+            },
+
+            onPointerUp() {
+                this.pointerTouchDown = null;
+            }
+        },
+        created(){
+            this.handleScroll = throttle(this.onScroll, 150, {leading: false});
+            this.pointerUpHandler = this.onPointerUp.bind(this), // because we need the same function to add and remove event handlers
+            this.pointerMoveHandler = throttle(this.onPointerMove, 50, {leading: false});
+        }
+    };
+
+</script>
diff --git a/src/index.js b/src/index.js
index 0b199739..036b224d 100644
--- a/src/index.js
+++ b/src/index.js
@@ -23,6 +23,7 @@ import Form from './components/form';
 import Icon from './components/icon';
 import Input from './components/input';
 import InputNumber from './components/input-number';
+import Scroll from './components/scroll';
 import LoadingBar from './components/loading-bar';
 import Menu from './components/menu';
 import Message from './components/message';
@@ -46,8 +47,8 @@ import Tooltip from './components/tooltip';
 import Transfer from './components/transfer';
 import Tree from './components/tree';
 import Upload from './components/upload';
-import { Row, Col } from './components/grid';
-import { Select, Option, OptionGroup } from './components/select';
+import {Row, Col} from './components/grid';
+import {Select, Option, OptionGroup} from './components/select';
 import locale from './locale';
 
 const iview = {
@@ -84,6 +85,7 @@ const iview = {
     Input,
     iInput: Input,
     InputNumber,
+    Scroll,
     LoadingBar,
     Menu,
     iMenu: Menu,
@@ -111,7 +113,7 @@ const iview = {
     Spin,
     Step: Steps.Step,
     Steps,
-    // Switch,
+	// Switch,
     iSwitch: Switch,
     iTable: Table,
     Table,
@@ -127,11 +129,11 @@ const iview = {
     Upload
 };
 
-const install = function (Vue, opts = {}) {
+const install = function(Vue, opts = {}) {
     locale.use(opts.locale);
     locale.i18n(opts.i18n);
 
-    Object.keys(iview).forEach((key) => {
+    Object.keys(iview).forEach(key => {
         Vue.component(key, iview[key]);
     });
 
@@ -147,4 +149,4 @@ if (typeof window !== 'undefined' && window.Vue) {
     install(window.Vue);
 }
 
-module.exports = Object.assign(iview, {install});   // eslint-disable-line no-undef
+module.exports = Object.assign(iview, {install}); // eslint-disable-line no-undef
diff --git a/src/styles/components/index.less b/src/styles/components/index.less
index a5190bb0..4d1c745b 100644
--- a/src/styles/components/index.less
+++ b/src/styles/components/index.less
@@ -13,6 +13,7 @@
 @import "checkbox";
 @import "switch";
 @import "input-number";
+@import "scroll";
 @import "tag";
 @import "loading-bar";
 @import "progress";
@@ -41,4 +42,4 @@
 @import "tree";
 @import "avatar";
 @import "color-picker";
-@import "auto-complete";
\ No newline at end of file
+@import "auto-complete";
diff --git a/src/styles/components/scroll.less b/src/styles/components/scroll.less
new file mode 100644
index 00000000..ff712059
--- /dev/null
+++ b/src/styles/components/scroll.less
@@ -0,0 +1,67 @@
+@scroll-prefix-cls: ~"@{css-prefix}scroll";
+
+.@{scroll-prefix-cls} {
+	&-wrapper {
+		width: auto;
+		margin: 0 auto;
+		position: relative;
+		outline: none;
+	}
+
+	&-container {
+		overflow-y: scroll;
+	}
+
+	&-content {
+		opacity: 1;
+		transition: opacity 0.5s;
+	}
+
+	&-content-loading {
+		opacity: 0.5;
+	}
+
+	&-loader {
+		text-align: center;
+		padding: 0px;
+		transition: padding 0.5s;
+	}
+}
+
+.@{scroll-prefix-cls}-loader-wrapper {
+	padding: 5px 0;
+	height: 0;
+	background-color: inherit;
+	transform: scale(0);
+	transition: opacity .3s, transform .5s, height .5s;
+
+	&-active {
+		height: 40px;
+		transform: scale(1);
+	}
+
+	@keyframes ani-demo-spin {
+		from {
+			transform: rotate(0deg);
+		}
+		50% {
+			transform: rotate(180deg);
+		}
+		to {
+			transform: rotate(360deg);
+		}
+	}
+
+	.@{scroll-prefix-cls}-spinner {
+		position: relative;
+	}
+
+	.@{scroll-prefix-cls}-spinner-icon {
+		animation: ani-demo-spin 1s linear infinite;
+	}
+}
+
+@media (max-width: 768px) {
+	.@{scroll-prefix-cls} {
+	}
+}