Make sure tooltip is oriented correctly when close to edge

We now check different tooltip orientations to make sure the best one is chosen. There are 2 cases that lead to reorientation:
1.  If the desired orientation (desiredPlace) is completely inside the client window, and the current orientation (place) is different from the desired one (then reorient to the desired orientation)
2.  If neither the desired orientation (desiredPlace) nor the current one (place) is inside the client window, but there are other orientations that are (then reorient to an arbitrary orientation that is inside)

All other cases will keep the orientation as it was before.

Author: gris-martin

src/utils/getPosition.js

@@ -52,139 +52,56 @@ export default function (e, target, node, place, desiredPlace, effect, offset) {
     return mouseY + offset_Y + extraOffset_Y
   }
 
-  // Judge if the tooltip has over the window(screen)
-  const outsideVertical = () => {
-    let result = false
-    let newPlace
-    if (getTipOffsetTop('left') < 0 &&
-      getTipOffsetBottom('left') <= windowHeight &&
-      getTipOffsetBottom('bottom') <= windowHeight) {
-      result = true
-      newPlace = 'bottom'
-    } else if (getTipOffsetBottom('left') > windowHeight &&
-      getTipOffsetTop('left') >= 0 &&
-      getTipOffsetTop('top') >= 0) {
-      result = true
-      newPlace = 'top'
-    }
-    return {result, newPlace}
-  }
-  const outsideLeft = () => {
-    let {result, newPlace} = outsideVertical() // Deal with vertical as first priority
-    if (result && outsideHorizontal().result) {
-      return {result: false} // No need to change, if change to vertical will out of space
-    }
-    if (!result && getTipOffsetLeft('left') < 0 && getTipOffsetRight('right') <= windowWidth) {
-      result = true // If vertical ok, but let out of side and right won't out of side
-      newPlace = 'right'
-    }
-    return {result, newPlace}
-  }
-  const outsideRight = () => {
-    let {result, newPlace} = outsideVertical()
-    if (result && outsideHorizontal().result) {
-      return {result: false} // No need to change, if change to vertical will out of space
-    }
-    if (!result && getTipOffsetRight('right') > windowWidth && getTipOffsetLeft('left') >= 0) {
-      result = true
-      newPlace = 'left'
-    }
-    return {result, newPlace}
-  }
-
-  const outsideHorizontal = () => {
-    let result = false
-    let newPlace
-    if (getTipOffsetLeft('top') < 0 &&
-      getTipOffsetRight('top') <= windowWidth &&
-      getTipOffsetRight('right') <= windowWidth) {
-      result = true
-      newPlace = 'right'
-    } else if (getTipOffsetRight('top') > windowWidth &&
-      getTipOffsetLeft('top') >= 0 &&
-      getTipOffsetLeft('left') >= 0) {
-      result = true
-      newPlace = 'left'
-    }
-    return {result, newPlace}
-  }
-  const outsideTop = () => {
-    let {result, newPlace} = outsideHorizontal()
-    if (result && outsideVertical().result) {
-      return {result: false}
-    }
-    if (!result && getTipOffsetTop('top') < 0 && getTipOffsetBottom('bottom') <= windowHeight) {
-      result = true
-      newPlace = 'bottom'
-    }
-    return {result, newPlace}
-  }
-  const outsideBottom = () => {
-    let {result, newPlace} = outsideHorizontal()
-    if (result && outsideVertical().result) {
-      return {result: false}
-    }
-    if (!result && getTipOffsetBottom('bottom') > windowHeight && getTipOffsetTop('top') >= 0) {
-      result = true
-      newPlace = 'top'
-    }
-    return {result, newPlace}
-  }
-
-  // Return new state to change the placement to the reverse if possible
-  const outsideLeftResult = outsideLeft()
-  const outsideRightResult = outsideRight()
-  const outsideTopResult = outsideTop()
-  const outsideBottomResult = outsideBottom()
-
-  if (place === 'left' && outsideLeftResult.result) {
-    return {
-      isNewState: true,
-      newState: {place: outsideLeftResult.newPlace}
-    }
-  } else if (place === 'right' && outsideRightResult.result) {
+  //
+  // Functions to test whether the tooltip's sides are inside 
+  // the client window for a given orientation p
+  //
+  //  _____________
+  // |             | <-- Right side
+  // | p = 'left'  |\
+  // |             |/  |\
+  // |_____________|   |_\  <-- Mouse
+  //      / \           |
+  //       |
+  //       |
+  //  Bottom side
+  //
+  let outsideLeft = p => getTipOffsetLeft(p) < 0
+  let outsideRight = p => getTipOffsetRight(p) > windowWidth
+  let outsideTop = p => getTipOffsetTop(p) < 0
+  let outsideBottom = p => getTipOffsetBottom(p) > windowHeight
+
+  // Check whether the tooltip with orientation p is completely inside the client window
+  let outside = p => outsideLeft(p) || outsideRight(p) || outsideTop(p) || outsideBottom(p)
+  let inside = p => !outside(p)
+
+  let placesList = ['left', 'right', 'top', 'bottom']
+  let insideList = []
+  for (let i = 0; i < 4; i++) {
+    let p = placesList[i]
+    if (inside(p)) {
+      insideList.push(p)
+    }
+  }
+
+  let isNewState = false
+  let newPlace
+  if (inside(desiredPlace) && desiredPlace !== place) {
+    isNewState = true
+    newPlace = desiredPlace
+  } else if (insideList.length > 0 && outside(desiredPlace) && outside(place)) {
+    isNewState = true
+    newPlace = insideList[0]
+  }
+  
+  if (isNewState)
+  {
     return {
       isNewState: true,
-      newState: {place: outsideRightResult.newPlace}
-    }
-  } else if (place === 'top' && outsideTopResult.result) {
-    return {
-      isNewState: true,
-      newState: {place: outsideTopResult.newPlace}
-    }
-  } else if (place === 'bottom' && outsideBottomResult.result) {
-    return {
-      isNewState: true,
-      newState: {place: outsideBottomResult.newPlace}
-    }
-  }
-
-  // Change back to original place if possible
-  if (place !== desiredPlace) {
-    if (desiredPlace === 'top' && !outsideTopResult.result) {
-      return {
-        isNewState: true,
-        newState: {place: 'top'}
-      }
-    } else if (desiredPlace === 'left' && !outsideLeftResult.result) {
-      return {
-        isNewState: true,
-        newState: {place: 'left'}
-      }
-    } else if (desiredPlace === 'right' && !outsideRightResult.result) {
-      return {
-        isNewState: true,
-        newState: {place: 'right'}
-      }
-    } else if (desiredPlace === 'bottom' && !outsideBottomResult.result) {
-      return {
-        isNewState: true,
-        newState: {place: 'bottom'}
-      }
+      newState: {place: newPlace}
     }
   }
 
-  // Return tooltip offset position
   return {
     isNewState: false,
     position: {