flow like the river

BACK_BACK/node_modules/htmlnano/lib/modules/collapseWhitespace.js

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+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.default = collapseWhitespace;
+
+var _helpers = require("../helpers");
+
+const noWhitespaceCollapseElements = new Set(['script', 'style', 'pre', 'textarea']);
+const noTrimWhitespacesArroundElements = new Set([// non-empty tags that will maintain whitespace around them
+'a', 'abbr', 'acronym', 'b', 'bdi', 'bdo', 'big', 'button', 'cite', 'code', 'del', 'dfn', 'em', 'font', 'i', 'ins', 'kbd', 'label', 'mark', 'math', 'nobr', 'object', 'q', 'rp', 'rt', 'rtc', 'ruby', 's', 'samp', 'select', 'small', 'span', 'strike', 'strong', 'sub', 'sup', 'svg', 'textarea', 'time', 'tt', 'u', 'var', // self-closing tags that will maintain whitespace around them
+'comment', 'img', 'input', 'wbr']);
+const noTrimWhitespacesInsideElements = new Set([// non-empty tags that will maintain whitespace within them
+'a', 'abbr', 'acronym', 'b', 'big', 'del', 'em', 'font', 'i', 'ins', 'kbd', 'mark', 'nobr', 'rp', 's', 'samp', 'small', 'span', 'strike', 'strong', 'sub', 'sup', 'time', 'tt', 'u', 'var']);
+const whitespacePattern = /\s+/g;
+const NONE = '';
+const SINGLE_SPACE = ' ';
+const validOptions = ['all', 'aggressive', 'conservative'];
+/** Collapses redundant whitespaces */
+
+function collapseWhitespace(tree, options, collapseType, tag) {
+  collapseType = validOptions.includes(collapseType) ? collapseType : 'conservative';
+  tree.forEach((node, index) => {
+    if (typeof node === 'string') {
+      const prevNode = tree[index - 1];
+      const nextNode = tree[index + 1];
+      const prevNodeTag = prevNode && prevNode.tag;
+      const nextNodeTag = nextNode && nextNode.tag;
+      const isTopLevel = !tag || tag === 'html' || tag === 'head';
+      const shouldTrim = collapseType === 'all' || isTopLevel ||
+      /*
+       * When collapseType is set to 'aggressive', and the tag is not inside 'noTrimWhitespacesInsideElements'.
+       * the first & last space inside the tag will be trimmed
+       */
+      collapseType === 'aggressive' && !noTrimWhitespacesInsideElements.has(tag);
+      node = collapseRedundantWhitespaces(node, collapseType, shouldTrim, tag, prevNodeTag, nextNodeTag);
+    }
+
+    const isAllowCollapseWhitespace = !noWhitespaceCollapseElements.has(node.tag);
+
+    if (node.content && node.content.length && isAllowCollapseWhitespace) {
+      node.content = collapseWhitespace(node.content, options, collapseType, node.tag);
+    }
+
+    tree[index] = node;
+  });
+  return tree;
+}
+
+function collapseRedundantWhitespaces(text, collapseType, shouldTrim = false, currentTag, prevNodeTag, nextNodeTag) {
+  if (!text || text.length === 0) {
+    return NONE;
+  }
+
+  if (!(0, _helpers.isComment)(text)) {
+    text = text.replace(whitespacePattern, SINGLE_SPACE);
+  }
+
+  if (shouldTrim) {
+    if (collapseType === 'aggressive') {
+      if (!noTrimWhitespacesArroundElements.has(prevNodeTag)) {
+        text = text.trimStart();
+      }
+
+      if (!noTrimWhitespacesArroundElements.has(nextNodeTag)) {
+        text = text.trimEnd();
+      }
+    } else {
+      // collapseType is 'all', trim spaces
+      text = text.trim();
+    }
+  }
+
+  return text;
+}