Sync partitionDurationFormatPattern with latest spec draft

Sync `partitionDurationFormatPattern` with the latest spec draft and
change it to use an `Intl.DurationFormat` object as the input, so it's
easier to compare it against the spec text and because it allows to test
more inputs.

Includes the fixes for:
- https://github.com/tc39/proposal-intl-duration-format/pull/183
- https://github.com/tc39/proposal-intl-duration-format/pull/184

harness/testIntl.js

@@ -2509,12 +2509,73 @@ function isCanonicalizedStructurallyValidTimeZoneName(timeZone) {
 /**
  * @description Simplified PartitionDurationFormatPattern implementation which
  * only supports the "en" locale.
+ * @param {Object} durationFormat the duration format object
  * @param {Object} duration the duration record
- * @param {String} style the duration format style
  * @result {Array} an array with formatted duration parts
  */
 
-function partitionDurationFormatPattern(duration, style = "short") {
+function partitionDurationFormatPattern(durationFormat, duration) {
+  function durationToFractional(duration, exponent) {
+    let {
+      seconds = 0,
+      milliseconds = 0,
+      microseconds = 0,
+      nanoseconds = 0,
+    } = duration;
+
+    // Directly return the duration amount when no sub-seconds are present.
+    switch (exponent) {
+      case 9: {
+        if (milliseconds === 0 && microseconds === 0 && nanoseconds === 0) {
+          return seconds;
+        }
+        break;
+      }
+      case 6: {
+        if (microseconds === 0 && nanoseconds === 0) {
+          return milliseconds;
+        }
+        break;
+      }
+      case 3: {
+        if (nanoseconds === 0) {
+          return microseconds;
+        }
+        break;
+      }
+    }
+
+    // Otherwise compute the overall amount of nanoseconds using BigInt to avoid
+    // loss of precision.
+    let ns = BigInt(nanoseconds);
+    switch (exponent) {
+      case 9:
+        ns += BigInt(seconds) * 1_000_000_000n;
+        // fallthrough
+      case 6:
+        ns += BigInt(milliseconds) * 1_000_000n;
+        // fallthrough
+      case 3:
+        ns += BigInt(microseconds) * 1_000n;
+        // fallthrough
+    }
+
+    let e = BigInt(10 ** exponent);
+
+    // Split the nanoseconds amount into an integer and its fractional part.
+    let q = ns / e;
+    let r = ns % e;
+
+    // Pad fractional part, without any leading negative sign, to |exponent| digits.
+    if (r < 0) {
+      r = -r;
+    }
+    r = String(r).padStart(exponent, "0");
+
+    // Return the result as a decimal string.
+    return `${q}.${r}`;
+  }
+
   const units = [
     "years",
     "months",
@@ -2528,39 +2589,7 @@ function partitionDurationFormatPattern(duration, style = "short") {
     "nanoseconds",
   ];
 
-  function durationToFractionalSeconds(duration) {
+  let options = durationFormat.resolvedOptions();
-    let {
-      seconds = 0,
-      milliseconds = 0,
-      microseconds = 0,
-      nanoseconds = 0,
-    } = duration;
-
-    // Directly return seconds when no sub-seconds are present.
-    if (milliseconds === 0 && microseconds === 0 && nanoseconds === 0) {
-      return seconds;
-    }
-
-    // Otherwise compute the overall amount of nanoseconds using BigInt to avoid
-    // loss of precision.
-    let ns_sec = BigInt(seconds) * 1_000_000_000n;
-    let ns_ms = BigInt(milliseconds) * 1_000_000n;
-    let ns_us = BigInt(microseconds) * 1_000n;
-    let ns = ns_sec + ns_ms + ns_us + BigInt(nanoseconds);
-
-    // Split the nanoseconds amount into seconds and sub-seconds.
-    let q = ns / 1_000_000_000n;
-    let r = ns % 1_000_000_000n;
-
-    // Pad sub-seconds, without any leading negative sign, to nine digits.
-    if (r < 0) {
-      r = -r;
-    }
-    r = String(r).padStart(9, "0");
-
-    // Return seconds with fractional part as a decimal string.
-    return `${q}.${r}`;
-  }
 
   // Only "en" is supported.
   const locale = "en";
@@ -2568,116 +2597,131 @@ function partitionDurationFormatPattern(duration, style = "short") {
   const timeSeparator = ":";
 
   let result = [];
-  let separated = false;
+  let needSeparator = false;
+  let displayNegativeSign = true;
 
   for (let unit of units) {
     // Absent units default to zero.
     let value = duration[unit] ?? 0;
 
-    let display = "auto";
+    let style = options[unit];
-    if (style === "digital") {
+    let display = options[unit + "Display"];
-      // Always display numeric units per GetDurationUnitOptions.
-      if (unit === "hours" || unit === "minutes" || unit === "seconds") {
-        display = "always";
-      }
 
-      // Numeric seconds and sub-seconds are combined into a single value.
+    // NumberFormat requires singular unit names.
-      if (unit === "seconds") {
+    let numberFormatUnit = unit.slice(0, -1);
-        value = durationToFractionalSeconds(duration);
+
+    // Compute the matching NumberFormat options.
+    let nfOpts = Object.create(null);
+
+    // Numeric seconds and sub-seconds are combined into a single value.
+    let done = false;
+    if (unit === "seconds" || unit === "milliseconds" || unit === "microseconds") {
+      let nextStyle = options[units[units.indexOf(unit) + 1]];
+      if (nextStyle === "numeric") {
+        if (unit === "seconds") {
+          value = durationToFractional(duration, 9);
+        } else if (unit === "milliseconds") {
+          value = durationToFractional(duration, 6);
+        } else {
+          value = durationToFractional(duration, 3);
+        }
+
+        nfOpts.maximumFractionDigits = options.fractionalDigits ?? 9;
+        nfOpts.minimumFractionDigits = options.fractionalDigits ?? 0;
+        nfOpts.roundingMode = "trunc";
+
+        done = true;
       }
     }
 
+    // Display zero numeric minutes when seconds will be displayed.
+    let displayRequired = false;
+    if (unit === "minutes" && needSeparator) {
+      displayRequired = options.secondsDisplay === "always" ||
+                        (duration.seconds ?? 0) !== 0 ||
+                        (duration.milliseconds ?? 0) !== 0 ||
+                        (duration.microseconds ?? 0) !== 0 ||
+                        (duration.nanoseconds ?? 0) !== 0;
+    }
+
     // "auto" display omits zero units.
-    if (value !== 0 || display !== "auto") {
+    if (value !== 0 || display !== "auto" || displayRequired) {
-      // Map the DurationFormat style to a NumberFormat style.
+      // Display only the first negative value.
-      let unitStyle = style;
+      if (displayNegativeSign) {
-      if (style === "digital") {
+        displayNegativeSign = false;
-        if (unit === "hours") {
+
-          unitStyle = "numeric";
+        // Set to negative zero to ensure the sign is displayed.
-        } else if (unit === "minutes" || unit === "seconds") {
+        if (value === 0) {
-          unitStyle = "2-digit";
+          let negative = units.some(unit => (duration[unit] ?? 0) < 0);
-        } else {
+          if (negative) {
-          unitStyle = "short";
+            value = -0;
+          }
         }
+      } else {
+        nfOpts.signDisplay = "never";
       }
 
-      // NumberFormat requires singular unit names.
+      nfOpts.numberingSystem = options.numberingSystem;
-      let numberFormatUnit = unit.slice(0, -1);
 
-      // Compute the matching NumberFormat options.
+      // If the value is formatted as a 2-digit numeric value.
-      let nfOpts;
+      if (style === "2-digit") {
-      if (unitStyle !== "numeric" && unitStyle !== "2-digit") {
+        nfOpts.minimumIntegerDigits = 2;
-        // The value is formatted as a standalone unit.
+      }
-        nfOpts = {
-          numberingSystem,
-          style: "unit",
-          unit: numberFormatUnit,
-          unitDisplay: unitStyle,
-        };
-      } else {
-        let roundingMode = undefined;
-        let minimumFractionDigits = undefined;
-        let maximumFractionDigits = undefined;
 
-        // Numeric seconds include any sub-seconds.
+      // If the value is formatted as a standalone unit.
-        if (style === "digital" && unit === "seconds") {
+      if (style !== "numeric" && style !== "2-digit") {
-          roundingMode = "trunc";
+        nfOpts.style = "unit";
-          minimumFractionDigits = 0;
+        nfOpts.unit = numberFormatUnit;
-          maximumFractionDigits = 9;
+        nfOpts.unitDisplay = style;
-        }
-
-        // The value is formatted as a numeric unit.
-        nfOpts = {
-          numberingSystem,
-          minimumIntegerDigits: (unitStyle === "2-digit" ? 2 : 1),
-          roundingMode,
-          minimumFractionDigits,
-          maximumFractionDigits,
-        };
       }
 
       let nf = new Intl.NumberFormat(locale, nfOpts);
-      let formatted = nf.formatToParts(value);
+
+      let list;
+      if (!needSeparator) {
+        list = [];
+      } else {
+        list = result[result.length - 1];
+
+        // Prepend the time separator before the formatted number.
+        list.push({
+          type: "literal",
+          value: timeSeparator,
+        });
+      }
+
+      // Format the numeric value.
+      let parts = nf.formatToParts(value);
 
       // Add |numberFormatUnit| to the formatted number.
-      let list = [];
+      for (let {value, type} of parts) {
-      for (let {value, type} of formatted) {
         list.push({type, value, unit: numberFormatUnit});
       }
 
-      if (!separated) {
+      if (!needSeparator) {
         // Prepend the separator before the next numeric unit.
-        if (unitStyle === "2-digit" || unitStyle === "numeric") {
+        if (style === "2-digit" || style === "numeric") {
-          separated = true;
+          needSeparator = true;
         }
 
         // Append the formatted number to |result|.
         result.push(list);
-      } else {
-        let last = result[result.length - 1];
-
-        // Prepend the time separator before the formatted number.
-        last.push({
-          type: "literal",
-          value: timeSeparator,
-        });
-
-        // Concatenate |last| and the formatted number.
-        last.push(...list);
       }
-    } else {
-      separated = false;
     }
 
-    // No further units possible after "seconds" when style is "digital".
+    if (done) {
-    if (style === "digital" && unit === "seconds") {
       break;
     }
   }
 
+  let listStyle = options.style;
+  if (listStyle === "digital") {
+    listStyle = "short";
+  }
+
   let lf = new Intl.ListFormat(locale, {
     type: "unit",
-    style: (style !== "digital" ? style : "short"),
+    style: listStyle,
   });
 
   // Collect all formatted units into a list of strings.
@@ -2705,11 +2749,12 @@ function partitionDurationFormatPattern(duration, style = "short") {
 
 /**
  * @description Return the formatted string from partitionDurationFormatPattern.
+ * @param {Object} durationFormat the duration format object
  * @param {Object} duration the duration record
- * @param {String} style the duration format style
  * @result {String} a string containing the formatted duration
  */
 
-function formatDurationFormatPattern(duration, style) {
+function formatDurationFormatPattern(durationFormat, duration) {
-  return partitionDurationFormatPattern(duration, style).reduce((acc, e) => acc + e.value, "");
+  let parts = partitionDurationFormatPattern(durationFormat, duration);
+  return parts.reduce((acc, e) => acc + e.value, "");
 }

test/intl402/DurationFormat/prototype/format/negative-duration-style-default-en.js

@@ -23,9 +23,10 @@ const duration = {
   nanoseconds: -9,
 };
 
-const expected = formatDurationFormatPattern(duration);
-
 const df = new Intl.DurationFormat("en");
+
+const expected = formatDurationFormatPattern(df, duration);
+
 assert.sameValue(
   df.format(duration),
   expected,

test/intl402/DurationFormat/prototype/format/negative-duration-style-short-en.js

@@ -25,9 +25,10 @@ const duration = {
   nanoseconds: -9,
 };
 
-const expected = formatDurationFormatPattern(duration, style);
-
 const df = new Intl.DurationFormat("en", {style});
+
+const expected = formatDurationFormatPattern(df, duration);
+
 assert.sameValue(
   df.format(duration),
   expected,

test/intl402/DurationFormat/prototype/format/negative-durationstyle-digital-en.js

@@ -25,9 +25,10 @@ const duration = {
   nanoseconds: -9,
 };
 
-const expected = formatDurationFormatPattern(duration, style);
-
 const df = new Intl.DurationFormat("en", {style});
+
+const expected = formatDurationFormatPattern(df, duration);
+
 assert.sameValue(
   df.format(duration),
   expected,

test/intl402/DurationFormat/prototype/format/negative-durationstyle-long-en.js

@@ -25,9 +25,10 @@ const duration = {
   nanoseconds: -9,
 };
 
-const expected = formatDurationFormatPattern(duration, style);
-
 const df = new Intl.DurationFormat("en", {style});
+
+const expected = formatDurationFormatPattern(df, duration);
+
 assert.sameValue(
   df.format(duration),
   expected,

test/intl402/DurationFormat/prototype/format/negative-durationstyle-narrow-en.js

@@ -25,9 +25,10 @@ const duration = {
   nanoseconds: -9,
 };
 
-const expected = formatDurationFormatPattern(duration, style);
-
 const df = new Intl.DurationFormat("en", {style});
+
+const expected = formatDurationFormatPattern(df, duration);
+
 assert.sameValue(
   df.format(duration),
   expected,

test/intl402/DurationFormat/prototype/format/precision-exact-mathematical-values.js

@@ -84,7 +84,7 @@ const durations = [
 const df = new Intl.DurationFormat("en", {style: "digital"});
 
 for (let duration of durations) {
-  let expected = formatDurationFormatPattern(duration, "digital");
+  let expected = formatDurationFormatPattern(df, duration);
   assert.sameValue(
     df.format(duration),
     expected,

test/intl402/DurationFormat/prototype/format/style-default-en.js

@@ -22,7 +22,8 @@ const duration = {
   nanoseconds: 9,
 };
 
-const expected = formatDurationFormatPattern(duration);
-
 const df = new Intl.DurationFormat("en");
+
+const expected = formatDurationFormatPattern(df, duration);
+
 assert.sameValue(df.format(duration), expected, `Assert DurationFormat format output using default style option`);

test/intl402/DurationFormat/prototype/format/style-digital-en.js

@@ -25,7 +25,8 @@ const duration = {
   nanoseconds: 9,
 };
 
-const expected = formatDurationFormatPattern(duration, style);
-
 const df = new Intl.DurationFormat("en", {style});
+
+const expected = formatDurationFormatPattern(df, duration);
+
 assert.sameValue(df.format(duration), expected, `Assert DurationFormat format output using ${style} style option`);

test/intl402/DurationFormat/prototype/format/style-long-en.js

@@ -24,7 +24,8 @@ const duration = {
   nanoseconds: 9,
 };
 
-const expected = formatDurationFormatPattern(duration, style);
-
 const df = new Intl.DurationFormat("en", {style});
+
+const expected = formatDurationFormatPattern(df, duration);
+
 assert.sameValue(df.format(duration), expected, `Assert DurationFormat format output using ${style} style option`);

test/intl402/DurationFormat/prototype/format/style-narrow-en.js

@@ -24,7 +24,8 @@ const duration = {
   nanoseconds: 9,
 };
 
-const expected = formatDurationFormatPattern(duration, style);
-
 const df = new Intl.DurationFormat("en", {style});
+
+const expected = formatDurationFormatPattern(df, duration);
+
 assert.sameValue(df.format(duration), expected, `Assert DurationFormat format output using ${style} style option`);

test/intl402/DurationFormat/prototype/format/style-short-en.js

@@ -24,7 +24,8 @@ const duration = {
   nanoseconds: 9,
 };
 
-const expected = formatDurationFormatPattern(duration, style);
-
 const df = new Intl.DurationFormat("en", {style});
+
+const expected = formatDurationFormatPattern(df, duration);
+
 assert.sameValue(df.format(duration), expected, `Assert DurationFormat format output using ${style} style option`);

test/intl402/DurationFormat/prototype/formatToParts/formatToParts-style-default-en.js

@@ -38,7 +38,8 @@ const duration = {
   nanoseconds: 789,
 };
 
-const expected = partitionDurationFormatPattern(duration);
+const df = new Intl.DurationFormat('en');
+
+const expected = partitionDurationFormatPattern(df, duration);
 
-let df = new Intl.DurationFormat('en');
 compare(df.formatToParts(duration), expected, `Using style : default`);

test/intl402/DurationFormat/prototype/formatToParts/formatToParts-style-digital-en.js

@@ -40,7 +40,8 @@ const duration = {
 
 const style = "digital";
 
-const expected = partitionDurationFormatPattern(duration, style);
+const df = new Intl.DurationFormat('en', { style });
+
+const expected = partitionDurationFormatPattern(df, duration);
 
-let df = new Intl.DurationFormat('en', { style });
 compare(df.formatToParts(duration), expected, `Using style : ${style}`);

test/intl402/DurationFormat/prototype/formatToParts/formatToParts-style-long-en.js

@@ -40,7 +40,8 @@ const duration = {
 
 const style = "long";
 
-const expected = partitionDurationFormatPattern(duration, style);
+const df = new Intl.DurationFormat('en', { style });
+
+const expected = partitionDurationFormatPattern(df, duration);
 
-let df = new Intl.DurationFormat('en', { style });
 compare(df.formatToParts(duration), expected, `Using style : ${style}`);

test/intl402/DurationFormat/prototype/formatToParts/formatToParts-style-narrow-en.js

@@ -40,7 +40,8 @@ const duration = {
 
 const style = "narrow";
 
-const expected = partitionDurationFormatPattern(duration, style);
+const df = new Intl.DurationFormat('en', { style });
+
+const expected = partitionDurationFormatPattern(df, duration);
 
-let df = new Intl.DurationFormat('en', { style });
 compare(df.formatToParts(duration), expected, `Using style : ${style}`);

test/intl402/DurationFormat/prototype/formatToParts/formatToParts-style-short-en.js

@@ -40,7 +40,8 @@ const duration = {
 
 const style = "short";
 
-const expected = partitionDurationFormatPattern(duration, style);
+const df = new Intl.DurationFormat('en', { style });
+
+const expected = partitionDurationFormatPattern(df, duration);
 
-let df = new Intl.DurationFormat('en', { style });
 compare(df.formatToParts(duration), expected, `Using style : ${style}`);

test/intl402/DurationFormat/prototype/formatToParts/negative-duration-formatToParts-style-default-en.js

@@ -41,7 +41,8 @@ const duration = {
   nanoseconds: -789,
 };
 
-const expected = partitionDurationFormatPattern(duration);
-
 const df = new Intl.DurationFormat("en");
+
+const expected = partitionDurationFormatPattern(df, duration);
+
 compare(df.formatToParts(duration), expected, `Using style : default`);

test/intl402/DurationFormat/prototype/formatToParts/negative-duration-formatToParts-style-digital-en.js

@@ -43,7 +43,8 @@ const duration = {
   nanoseconds: -789,
 };
 
-const expected = partitionDurationFormatPattern(duration, style);
-
 const df = new Intl.DurationFormat("en", { style });
+
+const expected = partitionDurationFormatPattern(df, duration);
+
 compare(df.formatToParts(duration), expected, `Using style : ${style}`);

test/intl402/DurationFormat/prototype/formatToParts/negative-duration-formatToParts-style-long-en.js

@@ -43,7 +43,8 @@ const duration = {
   nanoseconds: -789,
 };
 
-const expected = partitionDurationFormatPattern(duration, style);
-
 const df = new Intl.DurationFormat("en", { style });
+
+const expected = partitionDurationFormatPattern(df, duration);
+
 compare(df.formatToParts(duration), expected, `Using style : ${style}`);

test/intl402/DurationFormat/prototype/formatToParts/negative-duration-formatToParts-style-narrow-en.js

@@ -43,7 +43,8 @@ const duration = {
   nanoseconds: -789,
 };
 
-const expected = partitionDurationFormatPattern(duration, style);
-
 const df = new Intl.DurationFormat("en", { style });
+
+const expected = partitionDurationFormatPattern(df, duration);
+
 compare(df.formatToParts(duration), expected, `Using style : ${style}`);

test/intl402/DurationFormat/prototype/formatToParts/negative-duration-formatToParts-style-short-en.js

@@ -43,7 +43,8 @@ const duration = {
   nanoseconds: -789,
 };
 
-const expected = partitionDurationFormatPattern(duration, style);
-
 const df = new Intl.DurationFormat("en", { style });
+
+const expected = partitionDurationFormatPattern(df, duration);
+
 compare(df.formatToParts(duration), expected, `Using style : ${style}`);