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@bcks
Created January 31, 2021 14:57
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htmldiff
(function() {
var Match, calculate_operations, consecutive_where, create_index, diff, find_match, find_matching_blocks, html_to_tokens, is_end_of_tag, is_start_of_tag, is_tag, is_whitespace, isnt_tag, op_map, recursively_find_matching_blocks, render_operations, wrap;
is_end_of_tag = function(char) {
return char === '>';
};
is_start_of_tag = function(char) {
return char === '<';
};
is_whitespace = function(char) {
return /^\s+$/.test(char);
};
is_tag = function(token) {
return /^\s*<[^>]+>\s*$/.test(token);
};
isnt_tag = function(token) {
return !is_tag(token);
};
Match = (function() {
function Match(start_in_before, start_in_after, length) {
this.start_in_before = start_in_before;
this.start_in_after = start_in_after;
this.length = length;
this.end_in_before = (this.start_in_before + this.length) - 1;
this.end_in_after = (this.start_in_after + this.length) - 1;
}
return Match;
})();
html_to_tokens = function(html) {
var char, current_word, mode, words, _i, _len;
mode = 'char';
current_word = '';
words = [];
for (_i = 0, _len = html.length; _i < _len; _i++) {
char = html[_i];
switch (mode) {
case 'tag':
if (is_end_of_tag(char)) {
current_word += '>';
words.push(current_word);
current_word = '';
if (is_whitespace(char)) {
mode = 'whitespace';
} else {
mode = 'char';
}
} else {
current_word += char;
}
break;
case 'char':
if (is_start_of_tag(char)) {
if (current_word) {
words.push(current_word);
}
current_word = '<';
mode = 'tag';
} else if (/\s/.test(char)) {
if (current_word) {
words.push(current_word);
}
current_word = char;
mode = 'whitespace';
} else if (/[\w\#@]+/i.test(char)) {
current_word += char;
} else {
if (current_word) {
words.push(current_word);
}
current_word = char;
}
break;
case 'whitespace':
if (is_start_of_tag(char)) {
if (current_word) {
words.push(current_word);
}
current_word = '<';
mode = 'tag';
} else if (is_whitespace(char)) {
current_word += char;
} else {
if (current_word) {
words.push(current_word);
}
current_word = char;
mode = 'char';
}
break;
default:
throw new Error("Unknown mode " + mode);
}
}
if (current_word) {
words.push(current_word);
}
return words;
};
find_match = function(before_tokens, after_tokens, index_of_before_locations_in_after_tokens, start_in_before, end_in_before, start_in_after, end_in_after) {
var best_match_in_after, best_match_in_before, best_match_length, index_in_after, index_in_before, locations_in_after, looking_for, match, match_length_at, new_match_length, new_match_length_at, _i, _j, _len;
best_match_in_before = start_in_before;
best_match_in_after = start_in_after;
best_match_length = 0;
match_length_at = {};
for (index_in_before = _i = start_in_before; start_in_before <= end_in_before ? _i < end_in_before : _i > end_in_before; index_in_before = start_in_before <= end_in_before ? ++_i : --_i) {
new_match_length_at = {};
looking_for = before_tokens[index_in_before];
locations_in_after = index_of_before_locations_in_after_tokens[looking_for];
for (_j = 0, _len = locations_in_after.length; _j < _len; _j++) {
index_in_after = locations_in_after[_j];
if (index_in_after < start_in_after) {
continue;
}
if (index_in_after >= end_in_after) {
break;
}
if (match_length_at[index_in_after - 1] == null) {
match_length_at[index_in_after - 1] = 0;
}
new_match_length = match_length_at[index_in_after - 1] + 1;
new_match_length_at[index_in_after] = new_match_length;
if (new_match_length > best_match_length) {
best_match_in_before = index_in_before - new_match_length + 1;
best_match_in_after = index_in_after - new_match_length + 1;
best_match_length = new_match_length;
}
}
match_length_at = new_match_length_at;
}
if (best_match_length !== 0) {
match = new Match(best_match_in_before, best_match_in_after, best_match_length);
}
return match;
};
recursively_find_matching_blocks = function(before_tokens, after_tokens, index_of_before_locations_in_after_tokens, start_in_before, end_in_before, start_in_after, end_in_after, matching_blocks) {
var match;
match = find_match(before_tokens, after_tokens, index_of_before_locations_in_after_tokens, start_in_before, end_in_before, start_in_after, end_in_after);
if (match != null) {
if (start_in_before < match.start_in_before && start_in_after < match.start_in_after) {
recursively_find_matching_blocks(before_tokens, after_tokens, index_of_before_locations_in_after_tokens, start_in_before, match.start_in_before, start_in_after, match.start_in_after, matching_blocks);
}
matching_blocks.push(match);
if (match.end_in_before <= end_in_before && match.end_in_after <= end_in_after) {
recursively_find_matching_blocks(before_tokens, after_tokens, index_of_before_locations_in_after_tokens, match.end_in_before + 1, end_in_before, match.end_in_after + 1, end_in_after, matching_blocks);
}
}
return matching_blocks;
};
create_index = function(p) {
var idx, index, token, _i, _len, _ref;
if (p.find_these == null) {
throw new Error('params must have find_these key');
}
if (p.in_these == null) {
throw new Error('params must have in_these key');
}
index = {};
_ref = p.find_these;
for (_i = 0, _len = _ref.length; _i < _len; _i++) {
token = _ref[_i];
index[token] = [];
idx = p.in_these.indexOf(token);
while (idx !== -1) {
index[token].push(idx);
idx = p.in_these.indexOf(token, idx + 1);
}
}
return index;
};
find_matching_blocks = function(before_tokens, after_tokens) {
var index_of_before_locations_in_after_tokens, matching_blocks;
matching_blocks = [];
index_of_before_locations_in_after_tokens = create_index({
find_these: before_tokens,
in_these: after_tokens
});
return recursively_find_matching_blocks(before_tokens, after_tokens, index_of_before_locations_in_after_tokens, 0, before_tokens.length, 0, after_tokens.length, matching_blocks);
};
calculate_operations = function(before_tokens, after_tokens) {
var action_map, action_up_to_match_positions, index, is_single_whitespace, last_op, match, match_starts_at_current_position_in_after, match_starts_at_current_position_in_before, matches, op, operations, position_in_after, position_in_before, post_processed, _i, _j, _len, _len1;
if (before_tokens == null) {
throw new Error('before_tokens?');
}
if (after_tokens == null) {
throw new Error('after_tokens?');
}
position_in_before = position_in_after = 0;
operations = [];
action_map = {
'false,false': 'replace',
'true,false': 'insert',
'false,true': 'delete',
'true,true': 'none'
};
matches = find_matching_blocks(before_tokens, after_tokens);
matches.push(new Match(before_tokens.length, after_tokens.length, 0));
for (index = _i = 0, _len = matches.length; _i < _len; index = ++_i) {
match = matches[index];
match_starts_at_current_position_in_before = position_in_before === match.start_in_before;
match_starts_at_current_position_in_after = position_in_after === match.start_in_after;
action_up_to_match_positions = action_map[[match_starts_at_current_position_in_before, match_starts_at_current_position_in_after].toString()];
if (action_up_to_match_positions !== 'none') {
operations.push({
action: action_up_to_match_positions,
start_in_before: position_in_before,
end_in_before: (action_up_to_match_positions !== 'insert' ? match.start_in_before - 1 : void 0),
start_in_after: position_in_after,
end_in_after: (action_up_to_match_positions !== 'delete' ? match.start_in_after - 1 : void 0)
});
}
if (match.length !== 0) {
operations.push({
action: 'equal',
start_in_before: match.start_in_before,
end_in_before: match.end_in_before,
start_in_after: match.start_in_after,
end_in_after: match.end_in_after
});
}
position_in_before = match.end_in_before + 1;
position_in_after = match.end_in_after + 1;
}
post_processed = [];
last_op = {
action: 'none'
};
is_single_whitespace = function(op) {
if (op.action !== 'equal') {
return false;
}
if (op.end_in_before - op.start_in_before !== 0) {
return false;
}
return /^\s$/.test(before_tokens.slice(op.start_in_before, +op.end_in_before + 1 || 9e9));
};
for (_j = 0, _len1 = operations.length; _j < _len1; _j++) {
op = operations[_j];
if (((is_single_whitespace(op)) && last_op.action === 'replace') || (op.action === 'replace' && last_op.action === 'replace')) {
last_op.end_in_before = op.end_in_before;
last_op.end_in_after = op.end_in_after;
} else {
post_processed.push(op);
last_op = op;
}
}
return post_processed;
};
consecutive_where = function(start, content, predicate) {
var answer, index, last_matching_index, token, _i, _len;
content = content.slice(start, +content.length + 1 || 9e9);
last_matching_index = void 0;
for (index = _i = 0, _len = content.length; _i < _len; index = ++_i) {
token = content[index];
answer = predicate(token);
if (answer === true) {
last_matching_index = index;
}
if (answer === false) {
break;
}
}
if (last_matching_index != null) {
return content.slice(0, +last_matching_index + 1 || 9e9);
}
return [];
};
wrap = function(tag, content) {
var length, non_tags, position, rendering, tags;
rendering = '';
position = 0;
length = content.length;
while (true) {
if (position >= length) {
break;
}
non_tags = consecutive_where(position, content, isnt_tag);
position += non_tags.length;
if (non_tags.length !== 0) {
rendering += "<" + tag + ">" + (non_tags.join('')) + "</" + tag + ">";
}
if (position >= length) {
break;
}
tags = consecutive_where(position, content, is_tag);
position += tags.length;
rendering += tags.join('');
}
return rendering;
};
op_map = {
equal: function(op, before_tokens, after_tokens) {
return before_tokens.slice(op.start_in_before, +op.end_in_before + 1 || 9e9).join('');
},
insert: function(op, before_tokens, after_tokens) {
var val;
val = after_tokens.slice(op.start_in_after, +op.end_in_after + 1 || 9e9);
return wrap('ins', val);
},
"delete": function(op, before_tokens, after_tokens) {
var val;
val = before_tokens.slice(op.start_in_before, +op.end_in_before + 1 || 9e9);
return wrap('del', val);
}
};
op_map.replace = function(op, before_tokens, after_tokens) {
return (op_map["delete"](op, before_tokens, after_tokens)) + (op_map.insert(op, before_tokens, after_tokens));
};
render_operations = function(before_tokens, after_tokens, operations) {
var op, rendering, _i, _len;
rendering = '';
for (_i = 0, _len = operations.length; _i < _len; _i++) {
op = operations[_i];
rendering += op_map[op.action](op, before_tokens, after_tokens);
}
return rendering;
};
diff = function(before, after, callback) {
var ops;
if (before === after) {
return 0;
}
before = html_to_tokens(before);
after = html_to_tokens(after);
ops = calculate_operations(before, after);
callback( render_operations(before, after, ops) );
};
diff.html_to_tokens = html_to_tokens;
diff.find_matching_blocks = find_matching_blocks;
find_matching_blocks.find_match = find_match;
find_matching_blocks.create_index = create_index;
diff.calculate_operations = calculate_operations;
diff.render_operations = render_operations;
if (typeof define === 'function') {
define([], function() {
return diff;
});
} else if (typeof module !== "undefined" && module !== null) {
module.exports = diff;
} else {
this.htmldiff = diff;
}
}).call(this);
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