Implement "signMode" on Duration#toFormat

Author: diesieben07

src/duration.js

@@ -466,9 +466,13 @@ export default class Duration {
    * @param {string} fmt - the format string
    * @param {Object} opts - options
    * @param {boolean} [opts.floor=true] - floor numerical values
+   * @param {'negative'|'all'|'negativeLargestOnly'} [opts.signMode=negative] - How to handle signs
    * @example Duration.fromObject({ years: 1, days: 6, seconds: 2 }).toFormat("y d s") //=> "1 6 2"
    * @example Duration.fromObject({ years: 1, days: 6, seconds: 2 }).toFormat("yy dd sss") //=> "01 06 002"
    * @example Duration.fromObject({ years: 1, days: 6, seconds: 2 }).toFormat("M S") //=> "12 518402000"
+   * @example Duration.fromObject({ days: 6, seconds: 2 }).toFormat("d s", { signMode: "all" }) //=> "+6 +2"
+   * @example Duration.fromObject({ days: -6, seconds: -2 }).toFormat("d s", { signMode: "all" }) //=> "-6 -2"
+   * @example Duration.fromObject({ days: -6, seconds: -2 }).toFormat("d s", { signMode: "negativeLargestOnly" }) //=> "-6 2"
    * @return {string}
    */
   toFormat(fmt, opts = {}) {

src/impl/formatter.js

@@ -126,7 +126,7 @@ export default class Formatter {
     return this.dtFormatter(dt, opts).resolvedOptions();
   }
 
-  num(n, p = 0) {
+  num(n, p = 0, signDisplay = undefined) {
     // we get some perf out of doing this here, annoyingly
     if (this.opts.forceSimple) {
       return padStart(n, p);
@@ -137,6 +137,9 @@ export default class Formatter {
     if (p > 0) {
       opts.padTo = p;
     }
+    if (signDisplay) {
+      opts.signDisplay = signDisplay;
+    }
 
     return this.loc.numberFormatter(opts).format(n);
   }
@@ -372,6 +375,7 @@ export default class Formatter {
   }
 
   formatDurationFromString(dur, fmt) {
+    const invertLargest = this.opts.signMode === "negativeLargestOnly" ? -1 : 1;
     const tokenToField = (token) => {
         switch (token[0]) {
           case "S":
@@ -397,8 +401,17 @@ export default class Formatter {
       tokenToString = (lildur, info) => (token) => {
         const mapped = tokenToField(token);
         if (mapped) {
-          const inversionFactor = info.isNegativeDuration && mapped !== info.largestUnit ? -1 : 1;
-          return this.num(lildur.get(mapped) * inversionFactor, token.length);
+          const inversionFactor =
+            info.isNegativeDuration && mapped !== info.largestUnit ? invertLargest : 1;
+          let signDisplay;
+          if (this.opts.signMode === "negativeLargestOnly" && mapped !== info.largestUnit) {
+            signDisplay = "never";
+          } else if (this.opts.signMode === "all") {
+            signDisplay = "always";
+          } else {
+            signDisplay = "negative";
+          }
+          return this.num(lildur.get(mapped) * inversionFactor, token.length, signDisplay);
         } else {
           return token;
         }

test/duration/format.test.js

@@ -283,13 +283,84 @@ test("Duration#toFormat returns a lame string for invalid durations", () => {
   expect(Duration.invalid("because").toFormat("yy")).toBe("Invalid Duration");
 });
 
-test("Duration#toFormat shows negative sign on the largest unit", () => {
-  expect(Duration.fromObject({ years: -3, seconds: -45 }).toFormat("yyss")).toBe("-0345");
+// - signMode negativeLargestOnly
+
+test("Duration#toFormat shows negative sign on the largest unit when using signMode negativeLargestOnly", () => {
+  expect(
+    Duration.fromObject({ years: -3, seconds: -45 }).toFormat("yyss", {
+      signMode: "negativeLargestOnly",
+    })
+  ).toBe("-0345");
   expect(
-    Duration.fromObject({ years: -3, seconds: -45 }).toFormat("'before'yy'between'ss'after'")
+    Duration.fromObject({ years: -3, seconds: -45 }).toFormat("'before'yy'between'ss'after'", {
+      signMode: "negativeLargestOnly",
+    })
   ).toBe("before-03between45after");
   // Intentionally have the seconds not first to make sure years is still picked as the largest unit
-  expect(Duration.fromObject({ seconds: -45, years: -3 }).toFormat("ssyy")).toBe("45-03");
+  expect(
+    Duration.fromObject({ seconds: -45, years: -3 }).toFormat("ssyy", {
+      signMode: "negativeLargestOnly",
+    })
+  ).toBe("45-03");
+});
+
+test("Duration#toFormat shows no negative sign on the largest unit when using signMode negativeLargestOnly with positive Duration", () => {
+  expect(
+    Duration.fromObject({ years: 3, seconds: 45 }).toFormat("yyss", {
+      signMode: "negativeLargestOnly",
+    })
+  ).toBe("0345");
+  expect(
+    Duration.fromObject({ years: 3, seconds: 45 }).toFormat("'before'yy'between'ss'after'", {
+      signMode: "negativeLargestOnly",
+    })
+  ).toBe("before03between45after");
+  // Intentionally have the seconds not first to make sure years is still picked as the largest unit
+  expect(
+    Duration.fromObject({ years: 3, seconds: 45 }).toFormat("ssyy", {
+      signMode: "negativeLargestOnly",
+    })
+  ).toBe("4503");
+});
+
+// - signMode all
+
+test("Duration#toFormat with signMode all shows positive sign on positive durations", () => {
+  expect(
+    Duration.fromObject({ years: 3, seconds: 45 }).toFormat("yyss", {
+      signMode: "all",
+    })
+  ).toBe("+03+45");
+  expect(
+    Duration.fromObject({ years: 3, seconds: 45 }).toFormat("'before'yy'between'ss'after'", {
+      signMode: "all",
+    })
+  ).toBe("before+03between+45after");
+  // Intentionally have the seconds not first to make sure years is still picked as the largest unit
+  expect(
+    Duration.fromObject({ years: 3, seconds: 45 }).toFormat("ssyy", {
+      signMode: "all",
+    })
+  ).toBe("+45+03");
+});
+
+test("Duration#toFormat with signMode all shows positive sign on negative durations", () => {
+  expect(
+    Duration.fromObject({ years: -3, seconds: -45 }).toFormat("yyss", {
+      signMode: "all",
+    })
+  ).toBe("-03-45");
+  expect(
+    Duration.fromObject({ years: -3, seconds: -45 }).toFormat("'before'yy'between'ss'after'", {
+      signMode: "all",
+    })
+  ).toBe("before-03between-45after");
+  // Intentionally have the seconds not first to make sure years is still picked as the largest unit
+  expect(
+    Duration.fromObject({ years: -3, seconds: -45 }).toFormat("ssyy", {
+      signMode: "all",
+    })
+  ).toBe("-45-03");
 });
 
 //------