Deduplicate duration and number formatting internals

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RaRBJFZKSTA7naHGuQHfnQ

src/module/abbreviateNumber.js

@@ -6,6 +6,8 @@
 //   cindy.chang@dsp.im (Cindy Chang), 2024/5/30
 /** @module abbreviateNumber Duration abbreviation formatting. */
 
+import formatDuration from "./formatDuration.js";
+
 /**
  * Converts a total number of seconds into a human-readable abbreviated
  * duration string using days, hours, minutes, and seconds.
@@ -15,27 +17,7 @@
  *   or "0" if totalSeconds is zero.
  */
 export default function abbreviateNumber(totalSeconds) {
-  let seconds = 0;
+  const parsed = Number.parseInt(totalSeconds);
-  let minutes = 0;
+  if (parsed === 0) return "0";
-  let hours = 0;
+  return formatDuration(parsed, { separator: " " });
-  let days = 0;
-  let result = "";
-  let symbols = ["d", "h", "m", "s"];
-
-  totalSeconds = Number.parseInt(totalSeconds);
-  if (!Number.isNaN(totalSeconds)) {
-    seconds = totalSeconds % 60;
-    minutes = (Math.floor(totalSeconds - seconds) / 60) % 60;
-    hours = Math.floor(totalSeconds / 3600) % 24;
-    days = Math.floor(totalSeconds / (3600 * 24));
-  }
-
-  const units = [days, hours, minutes, seconds];
-  for (let i = 0; i < units.length; i++) {
-    if (units[i] > 0) result += units[i] + symbols[i] + " ";
-  }
-  result = result.trim();
-  if (totalSeconds === 0) result = "0";
-
-  return result;
 }

src/module/formatDuration.js

@@ -0,0 +1,71 @@
+// The Lucia project.
+// Copyright 2026 DSP, inc.  All rights reserved.
+// Authors:
+//   imacat.yang@dsp.im (imacat), 2026/7/5
+// AI assistance: Claude Code (Anthropic)
+/** @module formatDuration Shared duration formatting internals. */
+
+/**
+ * The duration units from the largest to the smallest.
+ *
+ * @constant {Array<{symbol: string, seconds: number}>}
+ */
+export const DURATION_UNITS = [
+  { symbol: "d", seconds: 24 * 60 * 60 },
+  { symbol: "h", seconds: 60 * 60 },
+  { symbol: "m", seconds: 60 },
+  { symbol: "s", seconds: 1 },
+];
+
+/**
+ * Picks the largest duration unit suitable for a number of seconds.
+ *
+ * @param {number} seconds - The number of seconds to pick a unit for.
+ * @param {boolean} [exclusive=false] - Whether a unit is chosen only
+ *   when the value is strictly greater than one unit (true), or when
+ *   it is greater than or equal to one unit (false).
+ * @returns {{symbol: string, seconds: number}} The chosen unit; falls
+ *   back to seconds when no larger unit qualifies.
+ */
+export function pickDurationUnit(seconds, exclusive = false) {
+  return DURATION_UNITS.find(
+    (unit) =>
+      unit.seconds === 1 ||
+      (exclusive ? seconds > unit.seconds : seconds >= unit.seconds),
+  );
+}
+
+/**
+ * Formats a duration in seconds as a day/hour/minute/second cascade.
+ *
+ * Zero-valued units are omitted, except that the seconds unit can be
+ * forced with the alwaysSeconds option. The result is truncated to at
+ * most maxUnits units, starting from the largest.
+ *
+ * @param {number} totalSeconds - The total number of seconds.
+ * @param {Object} [options] - The formatting options.
+ * @param {string} [options.separator=" "] - The string between units.
+ * @param {number} [options.maxUnits=Infinity] - The maximum number of
+ *   units to keep, starting from the largest.
+ * @param {boolean} [options.alwaysSeconds=false] - Whether to always
+ *   append the seconds unit, even when it is zero.
+ * @returns {string} The formatted duration (e.g. "2d 3h 15m 30s"), or
+ *   an empty string when no unit qualifies.
+ */
+export default function formatDuration(
+  totalSeconds,
+  { separator = " ", maxUnits = Infinity, alwaysSeconds = false } = {},
+) {
+  const seconds = totalSeconds % 60;
+  const minutes = (Math.floor(totalSeconds - seconds) / 60) % 60;
+  const hours = Math.floor(totalSeconds / 3600) % 24;
+  const days = Math.floor(totalSeconds / (3600 * 24));
+
+  const parts = [];
+  if (days > 0) parts.push(days + "d");
+  if (hours > 0) parts.push(hours + "h");
+  if (minutes > 0) parts.push(minutes + "m");
+  if (seconds > 0 || alwaysSeconds) parts.push(seconds + "s");
+
+  return parts.slice(0, maxUnits).join(separator);
+}

src/module/numberLabel.js

@@ -6,30 +6,18 @@
 //   cindy.chang@dsp.im (Cindy Chang), 2024/5/30
 /** @module numberLabel Number formatting with comma separators. */
 
-/**
- * Formats an integer string by inserting commas every three digits.
- * @param {string} numberStr - A string of digits to format.
- * @returns {string} The formatted string with commas (e.g. "1,000,000").
- */
-const formatNumberWithCommas = (numberStr) => {
-  let reversedStr = numberStr.split("").reverse().join("");
-  let groupedStr = reversedStr.match(/.{1,3}/g) || [];
-  let joinedStr = groupedStr.join(",");
-  let finalStr = joinedStr.split("").reverse().join("");
-
-  return finalStr;
-};
-
 /**
  * Converts a number to a string with comma-separated thousands.
  *
- * Handles decimal numbers by formatting only the integer part.
+ * Handles decimal numbers by formatting only the integer part. A comma
+ * is inserted before every group of three characters counted from the
+ * end of the integer part.
  *
  * @param {number} num - The number to format.
  * @returns {string} The formatted number string (e.g. "1,234.56").
  */
 export default function numberLabel(num) {
-  let parts = num.toString().split(".");
+  const parts = num.toString().split(".");
-  parts[0] = formatNumberWithCommas(parts[0]);
+  parts[0] = parts[0].replace(/(.)(?=(?:.{3})+$)/g, "$1,");
   return parts.join(".");
 }

src/module/setChartData.js

@@ -8,6 +8,8 @@
 
 import getMoment from "moment";
 
+import formatDuration, { DURATION_UNITS } from "./formatDuration.js";
+
 /**
  * Extends backend chart data with extrapolated boundary points for
  * line charts. Prepends a calculated minimum and appends a calculated
@@ -241,26 +243,8 @@ export function getXIndex(data, xValue) {
 export function formatTime(seconds) {
   if (Number.isNaN(Number(seconds))) {
     return null;
-  } else {
-    const remainingSeconds = seconds % 60;
-    const minutes = (Math.floor(seconds - remainingSeconds) / 60) % 60;
-    const hours = Math.floor(seconds / 3600) % 24;
-    const days = Math.floor(seconds / (3600 * 24));
-
-    let result = "";
-    if (days > 0) {
-      result += `${days}d`;
-    }
-    if (hours > 0) {
-      result += `${hours}h`;
-    }
-    if (minutes > 0) {
-      result += `${minutes}m`;
-    }
-    result += `${remainingSeconds}s`;
-
-    return result.trim(); // Remove trailing whitespace
   }
+  return formatDuration(seconds, { separator: "", alwaysSeconds: true });
 }
 /**
  * Truncates each time string to show only the two largest time units.
@@ -269,22 +253,23 @@ export function formatTime(seconds) {
  * @returns {Array<string>} Array of truncated strings (e.g. "2d 3h").
  */
 export function formatMaxTwo(times) {
-  const formattedTimes = [];
+  const secondsPerUnit = Object.fromEntries(
-  for (let time of times) {
+    DURATION_UNITS.map((unit) => [unit.symbol, unit.seconds]),
-    // Match numbers and units (days, hours, minutes, seconds); assume numbers have at most 10 digits
+  );
-    let units = time.match(/\d{1,10}[dhms]/g) || [];
+  return times.map((time) => {
-    let formattedTime = "";
+    // Match numbers and units (days, hours, minutes, seconds); assume
-    let count = 0;
+    // numbers have at most 10 digits.
-
+    const units = time.match(/\d{1,10}[dhms]/g);
-    // Keep only the two largest units
+    if (!units) return "";
-    for (let unit of units) {
+    const totalSeconds = units.reduce(
-      if (count >= 2) {
+      (sum, unit) =>
-        break;
+        sum + Number.parseInt(unit) * secondsPerUnit[unit.slice(-1)],
-      }
+      0,
-      formattedTime += unit + " ";
+    );
-      count++;
+    return formatDuration(totalSeconds, {
-    }
+      separator: " ",
-    formattedTimes.push(formattedTime.trim()); // Remove trailing whitespace
+      maxUnits: 2,
-  }
+      alwaysSeconds: units.some((unit) => unit.endsWith("s")),
-  return formattedTimes;
+    });
+  });
 }

src/module/timeLabel.js

@@ -8,6 +8,8 @@
 
 import moment from "moment";
 
+import { pickDurationUnit } from "./formatDuration.js";
+
 /** @constant {number} Number of decimal places for formatted time values. */
 const TOFIXED_DECIMAL = 1;
 
@@ -36,34 +38,11 @@ export const getStepSizeOfYTicks = (maxTimeInSecond, numOfParts) => {
  *   character ("d", "h", "m", or "s") and the converted time value.
  */
 const getTimeUnitAndValueToUse = (secondToDecide) => {
-  const day = 24 * 60 * 60;
+  const unit = pickDurationUnit(secondToDecide, true);
-  const hour = 60 * 60;
-  const minutes = 60;
-  const dd = secondToDecide / day;
-  const hh = secondToDecide / hour;
-  const mm = secondToDecide / minutes;
-
-  if (dd > 0 && dd > 1) {
   return {
-      unitToUse: "d",
+    unitToUse: unit.symbol,
-      timeValue: secondToDecide / day,
+    timeValue: secondToDecide / unit.seconds,
   };
-  } else if (hh > 0 && hh > 1) {
-    return {
-      unitToUse: "h",
-      timeValue: secondToDecide / hour,
-    };
-  } else if (mm > 0 && mm > 1) {
-    return {
-      unitToUse: "m",
-      timeValue: secondToDecide / minutes,
-    };
-  } else {
-    return {
-      unitToUse: "s",
-      timeValue: secondToDecide,
-    };
-  }
 };
 
 /**
@@ -80,6 +59,27 @@ export function getYTicksByIndex(stepSize, index, unitToUse) {
   return `${shortenStepsizeMultIndex}${unitToUse}`;
 }
 
+/**
+ * Formats seconds as a single-unit time label with the given suffixes.
+ *
+ * Chooses the largest unit whose size the value reaches. Values are
+ * rounded to fixedNumber decimal places, except seconds, which are
+ * concatenated as-is.
+ *
+ * @param {number} second - The total number of seconds.
+ * @param {number} fixedNumber - Number of decimal places.
+ * @param {{d: string, h: string, m: string, s: string}} suffixes - The
+ *   unit suffixes to append.
+ * @returns {string} The formatted time label.
+ */
+function scaledTimeLabel(second, fixedNumber, suffixes) {
+  const unit = pickDurationUnit(second);
+  if (unit.symbol === "s") {
+    return second + suffixes.s;
+  }
+  return (second / unit.seconds).toFixed(fixedNumber) + suffixes[unit.symbol];
+}
+
 /**
  * Converts seconds to a human-readable time string with full unit names.
  *
@@ -89,27 +89,12 @@ export function getYTicksByIndex(stepSize, index, unitToUse) {
  *   "30 mins", "5 sec").
  */
 export function getTimeLabel(second, fixedNumber = 0) {
-  const day = 24 * 60 * 60;
+  return scaledTimeLabel(second, fixedNumber, {
-  const hour = 60 * 60;
+    d: " days",
-  const minutes = 60;
+    h: " hrs",
-
+    m: " mins",
-  // The modulo operation limits the value to within one day (0 to 86399),
+    s: " sec",
-  // representing the remaining seconds after full days.
+  });
-  const dd = Math.floor(second / day);
-  const hh = Math.floor((second % day) / hour);
-  const mm = Math.floor((second % hour) / minutes);
-
-  if (dd > 0) {
-    return (second / day).toFixed(fixedNumber) + " days";
-  } else if (hh > 0) {
-    return ((second % day) / hour).toFixed(fixedNumber) + " hrs";
-  } else if (mm > 0) {
-    return ((second % hour) / minutes).toFixed(fixedNumber) + " mins";
-  }
-  if (second === 0) {
-    return second + " sec";
-  }
-  return second + " sec";
 }
 
 /**
@@ -123,24 +108,12 @@ export function getTimeLabel(second, fixedNumber = 0) {
  * @returns {string} The formatted string (e.g. "1d", "6.8h", "30m", "5s").
  */
 export function simpleTimeLabel(second, fixedNumber = 0) {
-  const day = 24 * 60 * 60;
+  return scaledTimeLabel(second, fixedNumber, {
-  const hour = 60 * 60;
+    d: "d",
-  const minutes = 60;
+    h: "h",
-  const dd = Math.floor(second / day);
+    m: "m",
-  const hh = Math.floor((second % day) / hour);
+    s: "s",
-  const mm = Math.floor((second % hour) / minutes);
+  });
-
-  if (dd > 0) {
-    return (second / day).toFixed(fixedNumber) + "d";
-  } else if (hh > 0) {
-    return ((second % day) / hour).toFixed(fixedNumber) + "h";
-  } else if (mm > 0) {
-    return ((second % hour) / minutes).toFixed(fixedNumber) + "m";
-  }
-  if (second === 0) {
-    return second + "s";
-  }
-  return second + "s";
 }
 /**
  * Converts seconds to a time string using the same unit as the maximum
@@ -155,52 +128,9 @@ export function simpleTimeLabel(second, fixedNumber = 0) {
  * @returns {string} The formatted string (e.g. "1.5d", "6.8h").
  */
 export function followTimeLabel(second, max, fixedNumber = 0) {
-  const day = 24 * 60 * 60;
+  const unit = pickDurationUnit(max, true);
-  const hour = 60 * 60;
+  const value = second / unit.seconds;
-  const minutes = 60;
+  return value.toFixed(value === 0 ? 0 : fixedNumber) + unit.symbol;
-
-  const dd = max / day;
-  const hh = max / hour;
-  const mm = max / minutes;
-  let maxUnit = "";
-  let result = "";
-
-  if (dd > 1) {
-    maxUnit = "d";
-  } else if (hh > 1) {
-    maxUnit = "h";
-  } else if (mm > 1) {
-    maxUnit = "m";
-  } else {
-    maxUnit = "s";
-  }
-  switch (maxUnit) {
-    case "d":
-      if (second / day === 0) {
-        fixedNumber = 0;
-      }
-      result = (second / day).toFixed(fixedNumber) + "d";
-      break;
-    case "h":
-      if (second / hour === 0) {
-        fixedNumber = 0;
-      }
-      result = (second / hour).toFixed(fixedNumber) + "h";
-      break;
-    case "m":
-      if (second / minutes === 0) {
-        fixedNumber = 0;
-      }
-      result = (second / minutes).toFixed(fixedNumber) + "m";
-      break;
-    case "s":
-      if (second === 0) {
-        fixedNumber = 0;
-      }
-      result = second.toFixed(fixedNumber) + "s";
-      break;
-  }
-  return result;
 }
 
 /**

tests/unit/module/formatDuration.test.js

@@ -0,0 +1,61 @@
+// The Lucia project.
+// Copyright 2026-2026 DSP, inc.  All rights reserved.
+// Authors:
+//   imacat.yang@dsp.im (imacat), 2026/7/5
+// AI assistance: Claude Code (Anthropic)
+
+import { describe, it, expect } from "vitest";
+import formatDuration, { pickDurationUnit } from "@/module/formatDuration.js";
+
+describe("formatDuration", () => {
+  it("formats a full cascade with the default separator", () => {
+    expect(formatDuration(93784)).toBe("1d 2h 3m 4s");
+  });
+
+  it("omits zero-valued units", () => {
+    expect(formatDuration(86400)).toBe("1d");
+    expect(formatDuration(3661)).toBe("1h 1m 1s");
+  });
+
+  it("returns an empty string when no unit qualifies", () => {
+    expect(formatDuration(0)).toBe("");
+    expect(formatDuration(NaN)).toBe("");
+  });
+
+  it("supports a custom separator", () => {
+    expect(formatDuration(90061, { separator: "" })).toBe("1d1h1m1s");
+  });
+
+  it("always appends seconds when alwaysSeconds is set", () => {
+    expect(formatDuration(0, { alwaysSeconds: true })).toBe("0s");
+    expect(formatDuration(60, { separator: "", alwaysSeconds: true })).toBe(
+      "1m0s",
+    );
+  });
+
+  it("truncates to maxUnits largest units", () => {
+    expect(formatDuration(93784, { maxUnits: 2 })).toBe("1d 2h");
+    expect(formatDuration(45, { maxUnits: 2 })).toBe("45s");
+  });
+});
+
+describe("pickDurationUnit", () => {
+  it("picks the largest unit reached by the value", () => {
+    expect(pickDurationUnit(86400).symbol).toBe("d");
+    expect(pickDurationUnit(3600).symbol).toBe("h");
+    expect(pickDurationUnit(60).symbol).toBe("m");
+    expect(pickDurationUnit(59).symbol).toBe("s");
+  });
+
+  it("requires strictly more than one unit when exclusive", () => {
+    expect(pickDurationUnit(86400, true).symbol).toBe("h");
+    expect(pickDurationUnit(86401, true).symbol).toBe("d");
+    expect(pickDurationUnit(60, true).symbol).toBe("s");
+    expect(pickDurationUnit(61, true).symbol).toBe("m");
+  });
+
+  it("falls back to seconds for zero and negative values", () => {
+    expect(pickDurationUnit(0).symbol).toBe("s");
+    expect(pickDurationUnit(-100).symbol).toBe("s");
+  });
+});