src/nodes/hashes.js in prettier-0.20.1 vs src/nodes/hashes.js in prettier-0.21.0

@@ -5,22 +5,13 @@
   indent,
   join,
   line,
   literalline
 } = require("../prettier");
-const { prefix, skipAssignIndent } = require("../utils");
 
-const nodeDive = (node, steps) => {
-  let current = node;
+const { nodeDive, prefix, skipAssignIndent } = require("../utils");
 
-  steps.forEach((step) => {
-    current = current[step];
-  });
-
-  return current;
-};
-
 // When attempting to convert a hash rocket into a hash label, you need to take
 // care because only certain patterns are allowed. Ruby source says that they
 // have to match keyword arguments to methods, but don't specify what that is.
 // After some experimentation, it looks like it's:
 //
@@ -63,10 +54,49 @@
     default:
       return concat([labelDoc, " =>"]);
   }
 };
 
+function printHash(path, { addTrailingCommas }, print) {
+  const hashNode = path.getValue();
+
+  // Hashes normally have a single assoclist_from_args child node. If it's
+  // missing, then it means we're dealing with an empty hash, so we can just
+  // exit here and print.
+  if (hashNode.body[0] === null) {
+    return "{}";
+  }
+
+  // Here we get a reference to the printed assoclist_from_args child node,
+  // which handles printing all of the key-value pairs of the hash. We're
+  // wrapping it in an array in case we need to append a trailing comma.
+  const assocDocs = [path.call(print, "body", 0)];
+
+  // Here we get a reference to the last key-value pair's value node, in order
+  // to check if we're dealing with a heredoc. If we are, then the trailing
+  // comma printing is handled from within the assoclist_from_args node
+  // printing, because the trailing comma has to go after the heredoc
+  // declaration.
+  const assocNodes = hashNode.body[0].body[0];
+  const lastAssocValueNode = assocNodes[assocNodes.length - 1].body[1];
+
+  // If we're adding a trailing comma and the last key-value pair's value node
+  // is not a heredoc node, then we can safely append the extra comma if the
+  // hash ends up getting printed on multiple lines.
+  if (addTrailingCommas && lastAssocValueNode.type !== "heredoc") {
+    assocDocs.push(ifBreak(",", ""));
+  }
+
+  return group(
+    concat([
+      "{",
+      indent(concat([line, concat(assocDocs)])),
+      concat([line, "}"])
+    ])
+  );
+}
+
 module.exports = {
   assoc_new: (path, opts, print) => {
     const valueDoc = path.call(print, "body", 1);
     const parts = [makeLabel(path, opts, print, ["body", 0])];
 
@@ -87,61 +117,31 @@
 
     assocNodes.forEach((assocNode, index) => {
       const isInner = index !== assocNodes.length - 1;
       const valueNode = assocNode.body[1];
 
-      const isStraightHeredoc = valueNode && valueNode.type === "heredoc";
-      const isSquigglyHeredoc =
-        valueNode &&
-        valueNode.type === "string_literal" &&
-        valueNode.body[0].type === "heredoc";
-
-      if (isStraightHeredoc || isSquigglyHeredoc) {
-        const heredocSteps = isStraightHeredoc
-          ? ["body", 1]
-          : ["body", 1, "body", 0];
-        const { beging, ending } = nodeDive(assocNode, heredocSteps);
-
+      if (valueNode && valueNode.type === "heredoc") {
         assocDocs.push(
           makeLabel(path, opts, print, ["body", 0, index, "body", 0]),
           " ",
-          beging,
+          valueNode.beging,
           isInner || addTrailingCommas ? "," : "",
           literalline,
-          concat(
-            path.map.apply(
-              path,
-              [print, "body", 0, index].concat(heredocSteps).concat("body")
-            )
-          ),
-          ending,
+          concat(path.map(print, "body", 0, index, "body", 1, "body")),
+          valueNode.ending,
           isInner ? line : ""
         );
       } else {
         assocDocs.push(path.call(print, "body", 0, index));
 
         if (isInner) {
           assocDocs.push(concat([",", line]));
-        } else if (addTrailingCommas) {
-          assocDocs.push(ifBreak(",", ""));
         }
       }
     });
 
     return group(concat(assocDocs));
   },
   bare_assoc_hash: (path, opts, print) =>
     group(join(concat([",", line]), path.map(print, "body", 0))),
-  hash: (path, opts, print) => {
-    if (path.getValue().body[0] === null) {
-      return "{}";
-    }
-
-    return group(
-      concat([
-        "{",
-        indent(concat([line, concat(path.map(print, "body"))])),
-        concat([line, "}"])
-      ])
-    );
-  }
+  hash: printHash
 };