feat(constructobservablemarble): implement constructobservablemarble

Author: kwonoj

src/assert/constructObservableMarble.ts

@@ -1,7 +1,139 @@
+import { ObservableMarbleToken } from '../marbles/ObservableMarbleToken';
+import { SubscriptionMarbleToken } from '../marbles/SubscriptionMarbleToken';
 import { TestMessage } from '../message/TestMessage';
 
-const constructObservableMarble = (_value: Array<TestMessage>) => {
-  //noop
+/**
+ * If marble provided custom values, we don't know original token - instead display
+ * pseudo alphabet for object based values. If custom value is single-length char or number,
+ * it'll be displayed as-is.
+ *
+ */
+const token = Array.from(
+  `äḅċḋëḟġḧïjḳḷṁṅöṗqṛṡẗüṿẅẍÿżÄḄĊḊЁḞĠḦЇJḲḶṀṄÖṖQṚṠṪÜṾẄẌŸŻ` +
+    `ⓐⓑⓒⓓⓔⓕⓖⓗⓘⓙⓚⓛⓜⓝⓞⓟⓠⓡⓢⓣⓤⓥⓦⓧⓨⓩⒶⒷⒸⒹⒺⒻⒼⒽⒾⒿⓀⓁⓂⓃⓄⓅⓆⓇⓈⓉⓊⓋⓌⓍⓎⓏ` +
+    `🅐🅑🅒🅓🅔🅕🅖🅗🅘🅙🅚🅛🅜🅝🅞🅟🅠🅡🅢🅣🅤🅥🅦🅧🅨🅩🅐🅑🅒🅓🅔🅕🅖🅗🅘🅙🅚🅛🅜🅝🅞🅟🅠🅡🅢🅣🅤🅥🅦🅧🅨🅩` +
+    `⒜⒝⒞⒟⒠⒡⒢⒣⒤⒥⒦⒧⒨⒩⒪⒫⒬⒭⒮⒯⒰⒱⒲⒳⒴⒵⒜⒝⒞⒟⒠⒡⒢⒣⒤⒥⒦⒧⒨⒩⒪⒫⒬⒭⒮⒯⒰⒱⒲⒳⒴⒵`
+);
+
+/**
+ * Take flattened array of test message, aggregate same-frame value into nested arrays.
+ *
+ */
+const marbleGroupReducer = <T>(
+  acc: Array<Array<TestMessage<T>>>,
+  value: TestMessage<T>
+): Array<Array<TestMessage<T>>> => {
+  const latestGroup = acc[acc.length - 1];
+  if (!latestGroup || latestGroup.length === 0) {
+    acc.push([value]);
+  } else {
+    const latestFrame = latestGroup[latestGroup.length - 1].frame;
+    if (value.frame === latestFrame) {
+      latestGroup.push(value);
+    } else {
+      acc.push([value]);
+    }
+  }
+  return acc;
+};
+
+//we don't restore identical marble to original - preserve metadata only
+const constructObservableMarble = <T = string>(
+  value: Array<TestMessage<T>> | Readonly<Array<TestMessage<T>>>
+): string => {
+  if (value.length === 0) {
+    return Array.from(Array(30)).map(() => ObservableMarbleToken.TIMEFRAME).join('');
+  }
+
+  const groupedMarble: Array<Array<TestMessage<T>>> = value.reduce(marbleGroupReducer, []);
+  const tokens = [...token];
+
+  let group: Array<TestMessage<T>>;
+  let completed: boolean = false;
+  let timeFrame: number = 0;
+  let marbleString = '';
+  let shiftedFrame: number = Number.NEGATIVE_INFINITY;
+
+  const appendNotificationValue = (message: TestMessage<T>) => {
+    const completed = message.notification.kind === 'C' || message.notification.kind === 'E';
+    if (completed) {
+      marbleString += message.notification.kind === 'C' ? ObservableMarbleToken.COMPLETE : ObservableMarbleToken.ERROR;
+      return true;
+    } else {
+      const value = message.notification.value;
+      if (value.toString().length === 1) {
+        marbleString += message.notification.value;
+      } else {
+        //we can't recover original token when notification metadata has custom value, use pseudo alphabet instead.
+        //do not support marble longer than predefined token char.
+        marbleString += tokens.shift();
+      }
+    }
+    return false;
+  };
+
+  //iterate each groups of message per timeframe
+  while ((group = groupedMarble.shift()!)) {
+    const single = group.length === 1;
+    let message: TestMessage<T>;
+
+    //interate each message in single group
+    while ((message = group.shift()!)) {
+      //determine if there's hot observable subscription, and value emitted before subscription
+      if (message.frame < 0 && shiftedFrame < 0) {
+        shiftedFrame = Math.abs(message.frame);
+      }
+
+      //calcuate frame and calibrate frame to start from 0
+      let adjustedFrame = shiftedFrame < 0 ? message.frame : message.frame + shiftedFrame;
+
+      //if frame's 0, value's immediately appended
+      if (adjustedFrame === 0) {
+        timeFrame++;
+      }
+
+      if (adjustedFrame !== 0) {
+        //if interval between message's long
+        if (adjustedFrame - timeFrame >= 15) {
+          while (timeFrame < adjustedFrame) {
+            marbleString += `-`;
+            const expandedTime = adjustedFrame - timeFrame - 2;
+            marbleString += `...${expandedTime}...-`;
+            timeFrame = adjustedFrame;
+          }
+        } else {
+          while (adjustedFrame !== 0 && timeFrame++ < adjustedFrame) {
+            marbleString +=
+              timeFrame === shiftedFrame + 1 ? SubscriptionMarbleToken.SUBSCRIBE : ObservableMarbleToken.TIMEFRAME;
+          }
+        }
+      }
+
+      //append single message value
+      if (single) {
+        if ((completed = appendNotificationValue(message))) {
+          break;
+        }
+      } else {
+        //append grouped message value
+        marbleString += `(`;
+        completed = appendNotificationValue(message);
+
+        while ((message = group.shift()!)) {
+          if ((completed = appendNotificationValue(message))) {
+            break;
+          }
+        }
+        marbleString += `)`;
+      }
+    }
+  }
+
+  if (!completed) {
+    marbleString += `-----`;
+  }
+
+  return marbleString;
 };
 
 export { constructObservableMarble };