a

backend/node_modules/mongoose/lib/helpers/projection/parseProjection.js

@@ -0,0 +1,38 @@
+'use strict';
+
+/**
+ * Convert a string or array into a projection object. Treats `-foo` as
+ * equivalent to `foo: 0` depending on `retainMinusPaths`. If `retainMinusPaths`
+ * is true, then `-foo` will be included in the projection as `'-foo': 0`.
+ *
+ * @param {object|string|string[]} v
+ * @param {boolean} [retainMinusPaths]
+ * @return {object}
+ */
+
+module.exports = function parseProjection(v, retainMinusPaths) {
+  const type = typeof v;
+
+  if (type === 'string') {
+    v = v.split(/\s+/);
+  }
+  if (!Array.isArray(v) && Object.prototype.toString.call(v) !== '[object Arguments]') {
+    return v;
+  }
+
+  const len = v.length;
+  const ret = {};
+  for (let i = 0; i < len; ++i) {
+    let field = v[i];
+    if (!field) {
+      continue;
+    }
+    const include = field.charAt(0) === '-' ? 0 : 1;
+    if (!retainMinusPaths && include === 0) {
+      field = field.slice(1);
+    }
+    ret[field] = include;
+  }
+
+  return ret;
+};