1 files changed, 35 insertions, 0 deletions
diff --git a/shell/lib/util.js b/shell/lib/util.js
new file mode 100644
index 00000000..6f87dfd7
--- /dev/null
+++ b/shell/lib/util.js
@@ -0,0 +1,35 @@
+export const inspect = arg => {
+  if (arg === null || typeof arg !== 'object') return arg;
+
+  try {
+    return JSON.stringify(arg, undefined, 2);
+  } catch (error) {
+    return '[Circular]';
+  }
+};
+
+const placeholderRegExp = /%[sdo%]/g;
+const placeholderHandlers = {
+  '%s': arg => String(arg),
+  '%d': arg => Number(arg),
+  '%o': arg => inspect(arg),
+};
+
+export const format = (fmt, ...args) => {
+  if (typeof fmt !== 'string') return args.map(inspect).join(' ');
+
+  const str = String(fmt).replace(placeholderRegExp, placeholder => {
+    if (placeholder === '%%') return '%';
+    if (!args.length) return placeholder;
+    const [arg] = args.splice(0, 1);
+    const handler = placeholderHandlers[placeholder];
+    return handler ? handler(arg) : placeholder;
+  });
+
+  return [str, ...args.map(inspect)].join(' ');
+};
+
+export const range = (start, end) => {
+  const size = end - start;
+  return new Array(size).map((v, i) => start + i);
+};