Add a well tested plugin

1 files changed, 248 insertions, 0 deletions

diff --git a/src/index.js b/src/index.js
new file mode 100644
index 0000000..ac3c426
--- /dev/null
+++ b/src/index.js
@@ -0,0 +1,248 @@
+'use strict';
+
+// A valid output which mean nothing has been parsed.
+// Used as error return / invalid output
+const nothingHappend = {
+  prop: {
+    key: undefined,
+    class: undefined,
+    id: undefined,
+  },
+  eaten: '',
+};
+
+// Main function
+function parse(value, indexNext = 0) {
+  let letsEat = '';
+  let stopOnBrace = false;
+  let errorDetected = false;
+
+  const prop = {key: undefined /* {} */, class: undefined /* [] */, id: undefined};
+
+  /* They is at leat one label and at best two */
+  /* ekqsdf <- one label
+   * qsdfqsfd=qsdfqsdf <- two */
+  let labelFirst = '';
+  let labelSecond;
+
+  /* 3 types :
+   * .azcv <- class
+   * #poi <- id
+   * dfgh=zert <- key
+   * lkj <- this is also a key but with a undefined value
+   */
+  let type;
+  const forbidenCharacters = '\n\r{}';
+
+  // A function that detect if it's time to end the parsing
+  const shouldStop = () => {
+    if (indexNext >= value.length || forbidenCharacters.indexOf(value[indexNext]) > -1) {
+      if (stopOnBrace && value[indexNext] !== '}') {
+        errorDetected = true;
+      }
+      return true;
+    }
+    return value[indexNext] === '}' && stopOnBrace;
+  };
+
+  let eaten = '';
+  // Couple of functions that parse same kinds of characters
+  // Used to parse spaces or identifiers
+  const eat = chars => {
+    eaten = '';
+
+    while (indexNext < value.length &&
+            forbidenCharacters.indexOf(value.charAt(indexNext)) < 0 &&
+            chars.indexOf(value.charAt(indexNext)) >= 0) {
+      letsEat += value.charAt(indexNext);
+      eaten += value.charAt(indexNext);
+      indexNext++;
+    }
+
+    return shouldStop();
+  };
+  const eatUntil = (chars, shouldSave) => {
+    eaten = '';
+
+    while (indexNext < value.length &&
+            forbidenCharacters.indexOf(value.charAt(indexNext)) < 0 &&
+            chars.indexOf(value.charAt(indexNext)) < 0) {
+      letsEat += value.charAt(indexNext);
+      eaten += value.charAt(indexNext);
+      indexNext++;
+    }
+
+    // Ugly but keep the main loop readable
+    if (shouldSave) {
+      if (labelFirst) {
+        labelSecond = eaten;
+      } else {
+        labelFirst = eaten;
+      }
+    }
+
+    return shouldStop();
+  };
+
+  const eatInQuote = quote => {
+    eaten = '';
+    if (value[indexNext] === quote) {
+      return;
+    }
+
+    while (indexNext < value.length &&
+          !(quote === value[indexNext] && value[indexNext - 1] !== '\\') &&
+          value[indexNext] !== '\n' && value[indexNext] !== '\r') {
+      letsEat += value.charAt(indexNext);
+      eaten += value.charAt(indexNext);
+      indexNext++;
+    }
+    if (value[indexNext] === '\n' || value[indexNext] === '\r' || indexNext >= value.length) {
+      errorDetected = true;
+      return true;
+    }
+
+    // Ugly but keep the main loop readable
+    if (labelFirst) {
+      labelSecond = eaten.replace(/\\"/g, '"');
+    } else {
+      labelFirst = eaten.replace(/\\"/g, '"');
+    }
+
+    return shouldStop();
+  };
+
+  // It's realy commun to eat only one character so let's make it a function
+  const eatOne = c => {
+    letsEat += c;
+    indexNext++;
+    return shouldStop();
+  };
+
+  const addAttribute = () => {
+    switch (type) {
+      case 'id': // ID
+        prop.id = prop.id || labelFirst;
+        break;
+      case 'class':
+        if (!prop.class) {
+          prop.class = [];
+        }
+
+        if (prop.class.indexOf(labelFirst) < 0) {
+          prop.class.push(labelFirst);
+        }
+
+        break;
+      case 'key':
+        if (!labelFirst) {
+          return nothingHappend;
+        }
+        if (labelFirst !== 'id' && labelFirst !== 'class') {
+          prop[labelFirst] = labelSecond;
+        }
+        break;
+      default:
+    }
+    type = undefined;
+    labelFirst = '';
+    labelSecond = undefined;
+  };
+
+  /** *********************** Start parsing ************************ */
+
+  // Let's check for trelling spaces first
+  eat(' \t\v');
+
+  if (value[indexNext] === '{') {
+    eatOne('{');
+    stopOnBrace = true;
+  }
+
+  while (!shouldStop()) {
+    if (eat(' \t\v')) {
+      break;
+    }
+
+    if (value.charAt(indexNext) === '.') { // Classes
+      type = 'class';
+      if (eatOne('.')) {
+        errorDetected = true;
+        break;
+      }
+    } else if (value.charAt(indexNext) === '#') { // ID
+      type = 'id';
+      if (eatOne('#')) {
+        errorDetected = true;
+        break;
+      }
+    } else { // Key
+      type = 'key';
+    }
+
+    // Extract name
+    if (eatUntil('=\t\b\v  ', true) || !labelFirst) {
+      break;
+    }
+    if (value.charAt(indexNext) === '=' && type === 'key') { // Set labelSecond
+      if (eatOne('=')) {
+        break;
+      }
+
+      if (value.charAt(indexNext) === '"') {
+        if (eatOne('"')) {
+          break;
+        }
+
+        if (eatInQuote('"')) {
+          break;
+        }
+
+        if (value.charAt(indexNext) === '"') {
+          if (eatOne('"')) {
+            break;
+          }
+        } else {
+          return nothingHappend;
+        }
+      } else if (value.charAt(indexNext) === '\'') {
+        if (eatOne('\'')) {
+          break;
+        }
+        if (eatInQuote('\'')) {
+          break;
+        }
+
+        if (value.charAt(indexNext) === '\'') {
+          if (eatOne('\'')) {
+            break;
+          }
+        } else {
+          return nothingHappend;
+        }
+      } else if (eatUntil(' \t\n\r\v=}', true)) {
+        break;
+      }
+    }
+
+    // Add the parsed attribute to the output prop with the ad hoc type
+    addAttribute();
+  }
+  addAttribute();
+  if (stopOnBrace) {
+    if (indexNext < value.length && value[indexNext] === '}') {
+      stopOnBrace = false;
+      eatOne('}');
+    } else {
+      return nothingHappend;
+    }
+  }
+
+  if (errorDetected) {
+    return nothingHappend;
+  }
+
+  return {prop, eaten: letsEat};
+}
+
+module.exports = parse;