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kms70847/addCollapseAndExpandButtonToEachCommentOnEachPageThatContainsCommentsOnHackerNews.user.js
Created
March 22, 2016 15:43
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var Post = function(node){ | |
this.node = node; | |
this.parent = undefined; | |
this.children = []; | |
this.isCollapsed = false; | |
} | |
Post.prototype.getIndentation = function(){ | |
var ind = this.node.getElementsByClassName("ind")[0]; | |
return ind.getElementsByTagName("IMG")[0].width / 40; | |
} | |
Post.prototype.getDescendants = function(){ | |
var result = []; | |
this.children.forEach(function(child){ | |
result.push(child); | |
Array.prototype.push.apply(result, child.getDescendants()); | |
}); | |
return result; | |
} | |
Post.prototype.hideBody = function(){ | |
var body = this.node.getElementsByClassName("comment")[0]; | |
body.style.display = "none"; | |
} | |
Post.prototype.showBody = function(){ | |
var body = this.node.getElementsByClassName("comment")[0]; | |
body.style.display = ""; | |
} | |
Post.prototype.hide = function(){ | |
this.node.style.display = "none"; | |
} | |
Post.prototype.show = function(){ | |
this.node.style.display = ""; | |
} | |
Post.prototype.collapse = function(){ | |
this.hideBody(); | |
this.isCollapsed = true; | |
this.getDescendants().forEach(function(descendant){ | |
descendant.hide(); | |
}); | |
} | |
Post.prototype.expand = function(post){ | |
this.showBody(); | |
this.isCollapsed = false; | |
this.children.forEach(function(child){ | |
child.show(); | |
if (!child.isCollapsed){ | |
child.expand(); | |
} | |
}); | |
} | |
Post.prototype.addCollapseButton = function(){ | |
var head = this.node.getElementsByClassName("comhead")[0]; | |
var button = makeToggleButton( | |
Post.prototype.collapse.bind(this), | |
Post.prototype.expand.bind(this) | |
); | |
head.appendChild(button); | |
} | |
function makeToggleButton(callbackA, callbackB){ | |
var button = document.createElement("A"); | |
var state = 0; | |
button.innerHTML = "[-]"; | |
button.onclick = function(){ | |
if (state == 0){ | |
button.innerHTML = "[+]"; | |
callbackA(); | |
state = 1; | |
} | |
else{ | |
button.innerHTML = "[-]"; | |
callbackB(); | |
state = 0; | |
} | |
}; | |
return button; | |
} | |
function getPostNodes(){ | |
var tree = document.getElementsByClassName("comment-tree")[0]; | |
return tree.getElementsByClassName("athing"); | |
} | |
function constructRelationships(posts){ | |
function top(seq){return seq[seq.length-1];} | |
function level(post){ return post == undefined ? -1 : post.getIndentation();} | |
var topLevelPosts = []; | |
var stack = [undefined]; | |
posts.forEach(function(post){ | |
while (level(top(stack)) >= level(post)){ | |
stack.pop(); | |
} | |
post.parent = top(stack); | |
if (top(stack) == undefined){ | |
topLevelPosts.push(post); | |
}else{ | |
top(stack).children.push(post); | |
post.parent = top(stack); | |
} | |
stack.push(post); | |
}); | |
return topLevelPosts; | |
} | |
try{ | |
var nodes = getPostNodes(); | |
var allPosts = []; | |
for (node of nodes){ | |
allPosts.push(new Post(node)); | |
} | |
constructRelationships(allPosts); | |
allPosts.forEach(function(post){ post.addCollapseButton(); }); | |
} | |
catch(e){ | |
console.log(e); | |
} |
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