Move writers into a separate directory

1 files changed, 176 insertions, 0 deletions

diff --git a/lib/writers/markdown-writer.js b/lib/writers/markdown-writer.js
new file mode 100644
index 0000000..b63d104
--- /dev/null
+++ b/lib/writers/markdown-writer.js
@@ -0,0 +1,176 @@
+
+var _ = require("underscore");
+
+function mdElement(start, end) {
+    if (end === undefined)
+        end = start;
+
+    this.open = function(attrs) {
+        return start;
+    };
+
+    this.close = function() {
+        return end;
+    };
+
+    this.empty = function(attrs) {
+        return this.open(attrs) + this.close();
+    };
+}
+function mdLink(link, text) {
+    var attrs = {};
+
+    this.open = function(attributes) {
+        attrs = attributes || {};
+
+        return "[";
+    };
+
+    this.close = function() {
+        return (attrs[text] || "") + "](" + (attrs[link] || "") + ")";
+    };
+
+    this.empty = function(attrs) {
+        // don't display empty content (this is mainly to remove images with no src data)
+        var content = this.open(attrs) + this.close();
+
+        if(content === "[]()") {
+            return "";
+        }
+
+        return content;
+    };
+}
+function mdList() {
+    this.open = function(attrs) {
+        return attrs.indent > -1 ? "\n" : "";
+    };
+
+    this.close = function(attrs) {
+        return attrs.indent > -1 ? "" : "\n";
+    };
+
+    this.empty = function(attrs) {
+        return this.open(attrs) + this.close();
+    };
+}
+function mdListItem() {
+    this.open = function(attrs) {
+        var output = "";
+
+        for(var i = 0; i < attrs.indent; ++i) {
+            output += "\t";
+        }
+
+        return output + (attrs.type === "ul" ? "-" : attrs.count + ".") + " ";
+    };
+
+    this.close = function() {
+        return "\n";
+    };
+
+    this.empty = function(attrs) {
+        return this.open(attrs) + this.close();
+    };
+}
+
+// map HTML tags to Markdown syntax
+var htmlmd = {
+    // paragraphs elements use three line feeds to close
+    // this prevents them being caught by collapsing list elements in `asString`
+    // while still allowing them to be collapsed when multiple empty lines are removed
+    "h1": new mdElement("# ", "\n\n\n"),
+    "h2": new mdElement("## ", "\n\n\n"),
+    "h3": new mdElement("### ", "\n\n\n"),
+    "h4": new mdElement("#### ", "\n\n\n"),
+    "h5": new mdElement("##### ", "\n\n\n"),
+    "h6": new mdElement("###### ", "\n\n\n"),
+    "p": new mdElement("", "\n\n\n"),
+    "br": new mdElement("", "  \n"),
+    "ul": new mdList(),
+    "ol": new mdList(),
+    "li": new mdListItem(),
+    "strong": new mdElement("**"),
+    "em": new mdElement("*"),
+    "a": new mdLink("href"),
+    "img": new mdLink("src", "alt"),
+};
+
+function mdWriter() {
+    var fragments = [];
+    var listStack = [];
+    var list = {
+        indent: -1,
+        type: "ul",
+        count: 0
+    };
+    
+    function isList(tagName) {
+        return tagName === "ul" || tagName === "ol";
+    }
+
+    function open(tagName, attributes) {
+        if(htmlmd[tagName]) {
+            attributes = attributes || {};
+
+            if(tagName === "li") {
+                attributes.indent = list.indent;
+                attributes.type = list.type;
+                attributes.count = ++list.count;
+            }
+            else if(isList(tagName)) {
+                attributes.indent = list.indent;
+            }
+
+            fragments.push(htmlmd[tagName].open(attributes));
+
+            if(isList(tagName)) {
+                listStack.push(_.clone(list));
+
+                list.type = tagName;
+                list.indent++;
+                list.count = 0;
+            }
+        }
+    }
+    
+    function close(tagName) {
+        if(htmlmd[tagName]) {
+            if(isList(tagName)) {
+                list = listStack.pop();
+            }
+
+            fragments.push(htmlmd[tagName].close(list));
+        }
+    }
+    
+    function selfClosing(tagName, attributes) {
+        if(htmlmd[tagName]) {
+            fragments.push(htmlmd[tagName].empty(attributes));
+        }
+    }
+    
+    function text(value) {
+        fragments.push(value);
+    }
+    
+    function append(html) {
+        fragments.push(html);
+    }
+    
+    function asString() {
+        // massage the output to collapse mulitple empty lines and empty lines between nested lists
+        return fragments.join("").replace(/\n{2}(\t*)([2-9]\d*\.|- )/g, "\n$1$2").replace(/\n{3,}/g, "\n\n");
+    }
+
+    return {
+        asString: asString,
+        open: open,
+        close: close,
+        text: text,
+        selfClosing: selfClosing,
+        append: append
+    };
+}
+
+exports.writer = mdWriter;
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