From e03ec093eceae8b26b6c206bdad6d2557a952858 Mon Sep 17 00:00:00 2001
From: David Nowinsky <david@nowinsky.net>
Date: Fri, 29 Nov 2019 15:25:59 +0100
Subject: [PATCH] Some type K abbreviations can be omitted in locale

---
 README.md               | 2 +-
 locale/fr-FR.json       | 3 ++-
 src/formatPrefixAuto.js | 6 ++++--
 src/formatTypes.js      | 4 ++--
 src/locale.js           | 5 ++++-
 test/locale-test.js     | 5 +++++
 6 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/README.md b/README.md
index 1f4d8ef..3f9415d 100644
--- a/README.md
+++ b/README.md
@@ -346,7 +346,7 @@ Returns a *locale* object for the specified *definition* with [*locale*.format](
 * `thousands` - the group separator (e.g., `","`).
 * `grouping` - the array of group sizes (e.g., `[3]`), cycled as needed.
 * `currency` - the currency prefix and suffix (e.g., `["$", ""]`).
-* `currencyAbbreviations` - the list of abbreviated suffixes for currency vales (array of 5 elements: units, thousands, millions, billions and trillions) (default `["", "K", "M", "B", "T"]`).
+* `currencyAbbreviations` - the list of abbreviated suffixes for currency values; an array of elements for each: units, thousands, millions, billions and trillions; defaults to `["", "K", "M", "B", "T"]`. The number of elements can vary.
 * `numerals` - optional; an array of ten strings to replace the numerals 0-9.
 * `percent` - optional; the percent sign (defaults to `"%"`).
 * `minus` - optional; the minus sign (defaults to hyphen-minus, `"-"`).
diff --git a/locale/fr-FR.json b/locale/fr-FR.json
index e0cf89d..349868d 100644
--- a/locale/fr-FR.json
+++ b/locale/fr-FR.json
@@ -3,5 +3,6 @@
   "thousands": "\u00a0",
   "grouping": [3],
   "currency": ["", "\u00a0€"],
-  "percent": "\u202f%"
+  "percent": "\u202f%",
+  "currencyAbbreviations": ["", "K", "Mio", "Mrd"]
 }
diff --git a/src/formatPrefixAuto.js b/src/formatPrefixAuto.js
index e3cc6bc..d11bce8 100644
--- a/src/formatPrefixAuto.js
+++ b/src/formatPrefixAuto.js
@@ -15,8 +15,10 @@ function formatSignificantDigitsForPrefixes(x, p, minPrefixOrder, maxPrefixOrder
       : "0." + new Array(1 - i).join("0") + formatDecimal(x, Math.max(0, p + i - 1))[0]; // less than the smallest prefix
 }
 
-export function formatCurrencyPrefixAuto(x, p) {
-  return formatSignificantDigitsForPrefixes(x, p, 0, 4);
+export function createFormatCurrencyPrefixAutoForLocale(currencyAbbreviations) {
+  return function formatCurrencyPrefixAuto(x, p) {
+    return formatSignificantDigitsForPrefixes(x, p, 0, currencyAbbreviations.length - 1);
+  }
 }
 
 export default function(x, p) {
diff --git a/src/formatTypes.js b/src/formatTypes.js
index 5327455..fd81632 100644
--- a/src/formatTypes.js
+++ b/src/formatTypes.js
@@ -1,4 +1,4 @@
-import formatPrefixAuto, { formatCurrencyPrefixAuto } from "./formatPrefixAuto.js";
+import formatPrefixAuto, { createFormatCurrencyPrefixAutoForLocale } from "./formatPrefixAuto.js";
 import formatRounded from "./formatRounded.js";
 
 export default {
@@ -9,7 +9,7 @@ export default {
   "e": function(x, p) { return x.toExponential(p); },
   "f": function(x, p) { return x.toFixed(p); },
   "g": function(x, p) { return x.toPrecision(p); },
-  "K": formatCurrencyPrefixAuto,
+  "K": createFormatCurrencyPrefixAutoForLocale, // depends of the current locale
   "o": function(x) { return Math.round(x).toString(8); },
   "p": function(x, p) { return formatRounded(x * 100, p); },
   "r": formatRounded,
diff --git a/src/locale.js b/src/locale.js
index afc2049..3a97be7 100644
--- a/src/locale.js
+++ b/src/locale.js
@@ -56,6 +56,9 @@ export default function(locale) {
     var formatType = formatTypes[type],
         maybeSuffix = /[defgKprs%]/.test(type);
 
+    if (type === 'K')
+      formatType = formatType(currencyAbbreviations);
+
     // Set the default precision if not specified,
     // or clamp the specified precision to the supported range.
     // For significant precision, it must be in [1, 21].
@@ -151,7 +154,7 @@ export default function(locale) {
   }
 
   var formatPrefix = createFormatPrefix(SIprefixes, -8, 8);
-  var formatCurrencyPrefix = createFormatPrefix(currencyAbbreviations, 0, 4);
+  var formatCurrencyPrefix = createFormatPrefix(currencyAbbreviations, 0, currencyAbbreviations.length - 1);
 
   return {
     format: newFormat,
diff --git a/test/locale-test.js b/test/locale-test.js
index 494a09c..48c21dd 100644
--- a/test/locale-test.js
+++ b/test/locale-test.js
@@ -26,6 +26,11 @@ tape("formatLocale({currencyAbbreviations: [list of abbreviations]}) should abbr
   test.end();
 });
 
+tape("formatLocale({currencyAbbreviations: [list of abbreviations]}) should abbreviate only specified levels", function (test) {
+  test.equal(d3.formatLocale({ currencyAbbreviations: ["", "M", "Mio", "Mrd"] }).format("$.3K")(1.2e12), "1200Mrd");
+  test.end();
+});
+
 tape("formatLocale({grouping: undefined}) does not perform any grouping", function(test) {
   test.equal(d3.formatLocale({decimal: "."}).format("012,.2f")(2), "000000002.00");
   test.end();