flow like the river

VISUALIZACION/node_modules/graphql/jsutils/promiseReduce.js

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+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.default = promiseReduce;
+
+var _isPromise = _interopRequireDefault(require("./isPromise.js"));
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
+
+/**
+ * Similar to Array.prototype.reduce(), however the reducing callback may return
+ * a Promise, in which case reduction will continue after each promise resolves.
+ *
+ * If the callback does not return a Promise, then this function will also not
+ * return a Promise.
+ */
+function promiseReduce(values, callback, initialValue) {
+  return values.reduce(function (previous, value) {
+    return (0, _isPromise.default)(previous) ? previous.then(function (resolved) {
+      return callback(resolved, value);
+    }) : callback(previous, value);
+  }, initialValue);
+}