--- /dev/null
+'use strict';
+
+var trim = require('trim');
+var whitespace = require('is-whitespace-character');
+var locate = require('../locate/strong');
+
+module.exports = strong;
+strong.locator = locate;
+
+var C_ASTERISK = '*';
+var C_UNDERSCORE = '_';
+
+function strong(eat, value, silent) {
+ var self = this;
+ var index = 0;
+ var character = value.charAt(index);
+ var now;
+ var pedantic;
+ var marker;
+ var queue;
+ var subvalue;
+ var length;
+ var prev;
+
+ if (
+ (character !== C_ASTERISK && character !== C_UNDERSCORE) ||
+ value.charAt(++index) !== character
+ ) {
+ return;
+ }
+
+ pedantic = self.options.pedantic;
+ marker = character;
+ subvalue = marker + marker;
+ length = value.length;
+ index++;
+ queue = '';
+ character = '';
+
+ if (pedantic && whitespace(value.charAt(index))) {
+ return;
+ }
+
+ while (index < length) {
+ prev = character;
+ character = value.charAt(index);
+
+ if (
+ character === marker &&
+ value.charAt(index + 1) === marker &&
+ (!pedantic || !whitespace(prev))
+ ) {
+ character = value.charAt(index + 2);
+
+ if (character !== marker) {
+ if (!trim(queue)) {
+ return;
+ }
+
+ /* istanbul ignore if - never used (yet) */
+ if (silent) {
+ return true;
+ }
+
+ now = eat.now();
+ now.column += 2;
+ now.offset += 2;
+
+ return eat(subvalue + queue + subvalue)({
+ type: 'strong',
+ children: self.tokenizeInline(queue, now)
+ });
+ }
+ }
+
+ if (!pedantic && character === '\\') {
+ queue += character;
+ character = value.charAt(++index);
+ }
+
+ queue += character;
+ index++;
+ }
+}