From ef6a2c5f8a448bb16bcbaeab06f29e2be98a958d Mon Sep 17 00:00:00 2001
From: fisker Cheung <lionkay@gmail.com>
Date: Mon, 16 Nov 2020 08:56:45 +0800
Subject: [PATCH] Refactor: Simplify markdown table print (#9660)

---
 src/language-markdown/printer-markdown.js | 115 ++++++++--------------
 1 file changed, 43 insertions(+), 72 deletions(-)

diff --git a/src/language-markdown/printer-markdown.js b/src/language-markdown/printer-markdown.js
index 5ea2257b8..ec0644bc1 100644
--- a/src/language-markdown/printer-markdown.js
+++ b/src/language-markdown/printer-markdown.js
@@ -41,6 +41,10 @@ const {
   isAutolink,
 } = require("./utils");
 
+/**
+ * @typedef {import("../document").Doc} Doc
+ */
+
 const TRAILING_HARDLINE_NODES = new Set(["importExport"]);
 const SINGLE_LINE_NODE_TYPES = ["heading", "tableCell", "link", "wikiLink"];
 const SIBLING_NODE_TYPES = new Set([
@@ -577,37 +581,34 @@ function printTable(path, options, print) {
   const hardlineWithoutBreakParent = hardline.parts[0];
   const node = path.getValue();
 
-  // { [rowIndex: number]: { [columnIndex: number]: string } }
+  const columnMaxWidths = [];
+  // { [rowIndex: number]: { [columnIndex: number]: {text: string, width: number} } }
   const contents = path.map(
     (rowPath) =>
-      rowPath.map(
-        (cellPath) => printDocToString(cellPath.call(print), options).formatted,
-        "children"
-      ),
+      rowPath.map((cellPath, columnIndex) => {
+        const text = printDocToString(cellPath.call(print), options).formatted;
+        const width = getStringWidth(text);
+        columnMaxWidths[columnIndex] = Math.max(
+          columnMaxWidths[columnIndex] || 3, // minimum width = 3 (---, :--, :-:, --:)
+          width
+        );
+        return { text, width };
+      }, "children"),
     "children"
   );
 
-  // Get the width of each column
-  const columnMaxWidths = contents.reduce(
-    (currentWidths, rowContents) =>
-      currentWidths.map((width, columnIndex) =>
-        Math.max(width, getStringWidth(rowContents[columnIndex]))
-      ),
-    contents[0].map(() => 3) // minimum width = 3 (---, :--, :-:, --:)
-  );
   const alignedTable = printTableContents(/* isCompact */ false);
-
   if (options.proseWrap !== "never") {
     return concat([breakParent, alignedTable]);
   }
 
   // Only if the --prose-wrap never is set and it exceeds the print width.
   const compactTable = printTableContents(/* isCompact */ true);
-
   return concat([breakParent, group(ifBreak(compactTable, alignedTable))]);
 
   function printTableContents(isCompact) {
-    const parts = [printRow(contents[0], isCompact), printSeparator(isCompact)];
+    /** @type{Doc[]} */
+    const parts = [printRow(contents[0], isCompact), printAlign(isCompact)];
     if (contents.length > 1) {
       parts.push(
         join(
@@ -621,66 +622,36 @@ function printTable(path, options, print) {
     return join(hardlineWithoutBreakParent, parts);
   }
 
-  function printSeparator(isCompact) {
-    return concat([
-      "| ",
-      join(
-        " | ",
-        columnMaxWidths.map((width, index) => {
-          const spaces = isCompact ? 3 : width;
-          switch (node.align[index]) {
-            case "left":
-              return ":" + "-".repeat(spaces - 1);
-            case "right":
-              return "-".repeat(spaces - 1) + ":";
-            case "center":
-              return ":" + "-".repeat(spaces - 2) + ":";
-            default:
-              return "-".repeat(spaces);
-          }
-        })
-      ),
-      " |",
-    ]);
+  function printAlign(isCompact) {
+    const align = columnMaxWidths.map((width, index) => {
+      const align = node.align[index];
+      const first = align === "center" || align === "left" ? ":" : "-";
+      const last = align === "center" || align === "right" ? ":" : "-";
+      const middle = isCompact ? "-" : "-".repeat(width - 2);
+      return `${first}${middle}${last}`;
+    });
+
+    return `| ${align.join(" | ")} |`;
   }
 
   function printRow(rowContents, isCompact) {
-    return concat([
-      "| ",
-      join(
-        " | ",
-        isCompact
-          ? rowContents
-          : rowContents.map((rowContent, columnIndex) => {
-              switch (node.align[columnIndex]) {
-                case "right":
-                  return alignRight(rowContent, columnMaxWidths[columnIndex]);
-                case "center":
-                  return alignCenter(rowContent, columnMaxWidths[columnIndex]);
-                default:
-                  return alignLeft(rowContent, columnMaxWidths[columnIndex]);
-              }
-            })
-      ),
-      " |",
-    ]);
-  }
+    const columns = rowContents.map(({ text, width }, columnIndex) => {
+      if (isCompact) {
+        return text;
+      }
+      const spaces = columnMaxWidths[columnIndex] - width;
+      const align = node.align[columnIndex];
+      let before = 0;
+      if (align === "right") {
+        before = spaces;
+      } else if (align === "center") {
+        before = Math.floor(spaces / 2);
+      }
+      const after = spaces - before;
+      return `${" ".repeat(before)}${text}${" ".repeat(after)}`;
+    });
 
-  function alignLeft(text, width) {
-    const spaces = width - getStringWidth(text);
-    return concat([text, " ".repeat(spaces)]);
-  }
-
-  function alignRight(text, width) {
-    const spaces = width - getStringWidth(text);
-    return concat([" ".repeat(spaces), text]);
-  }
-
-  function alignCenter(text, width) {
-    const spaces = width - getStringWidth(text);
-    const left = Math.floor(spaces / 2);
-    const right = spaces - left;
-    return concat([" ".repeat(left), text, " ".repeat(right)]);
+    return `| ${columns.join(" | ")} |`;
   }
 }