Add markdown preview, update rust.vim

sources_non_forked/markdown-preview.nvim/app/pages/chart.js

@@ -0,0 +1,34 @@
+import Chart from 'chart.js'
+
+function render () {
+  document.querySelectorAll('.chartjs').forEach(element => {
+    try {
+      // eslint-disable-next-line no-new
+      new Chart(element, JSON.parse(element.textContent))
+    } catch (e) {
+      element.outerHTML = `<pre>Chart.js complains: "${e}"</pre>`
+    }
+  })
+}
+
+const chartPlugin = (md) => {
+  const temp = md.renderer.rules.fence.bind(md.renderer.rules)
+  md.renderer.rules.fence = (tokens, idx, options, env, slf) => {
+    const token = tokens[idx]
+    if (token.info && token.info.trim() === 'chart') {
+      const code = token.content.trim()
+      try {
+        const json = JSON.parse(code)
+        return `<canvas class="chartjs">${JSON.stringify(json)}</canvas>`
+      } catch (e) { // JSON.parse exception
+        return `<pre>${e}</pre>`
+      }
+    }
+    return temp(tokens, idx, options, env, slf)
+  }
+}
+
+export default {
+  render,
+  chartPlugin
+}