doevisualizations
Version:
Data Visualization Library based on RequireJS and D3.js (v4+)
129 lines (106 loc) • 4.96 kB
JavaScript
import exponent from "./exponent";
import formatGroup from "./formatGroup";
import formatNumerals from "./formatNumerals";
import formatSpecifier from "./formatSpecifier";
import formatTypes from "./formatTypes";
import {prefixExponent} from "./formatPrefixAuto";
import identity from "./identity";
var prefixes = ["y","z","a","f","p","n","µ","m","","k","M","G","T","P","E","Z","Y"];
export default function(locale) {
var group = locale.grouping && locale.thousands ? formatGroup(locale.grouping, locale.thousands) : identity,
currency = locale.currency,
decimal = locale.decimal,
numerals = locale.numerals ? formatNumerals(locale.numerals) : identity,
percent = locale.percent || "%";
function newFormat(specifier) {
specifier = formatSpecifier(specifier);
var fill = specifier.fill,
align = specifier.align,
sign = specifier.sign,
symbol = specifier.symbol,
zero = specifier.zero,
width = specifier.width,
comma = specifier.comma,
precision = specifier.precision,
type = specifier.type;
// Compute the prefix and suffix.
// For SI-prefix, the suffix is lazily computed.
var prefix = symbol === "$" ? currency[0] : symbol === "#" && /[boxX]/.test(type) ? "0" + type.toLowerCase() : "",
suffix = symbol === "$" ? currency[1] : /[%p]/.test(type) ? percent : "";
// What format function should we use?
// Is this an integer type?
// Can this type generate exponential notation?
var formatType = formatTypes[type],
maybeSuffix = !type || /[defgprs%]/.test(type);
// 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].
// For fixed precision, it must be in [0, 20].
precision = precision == null ? (type ? 6 : 12)
: /[gprs]/.test(type) ? Math.max(1, Math.min(21, precision))
: Math.max(0, Math.min(20, precision));
function format(value) {
var valuePrefix = prefix,
valueSuffix = suffix,
i, n, c;
if (type === "c") {
valueSuffix = formatType(value) + valueSuffix;
value = "";
} else {
value = +value;
// Perform the initial formatting.
var valueNegative = value < 0;
value = formatType(Math.abs(value), precision);
// If a negative value rounds to zero during formatting, treat as positive.
if (valueNegative && +value === 0) valueNegative = false;
// Compute the prefix and suffix.
valuePrefix = (valueNegative ? (sign === "(" ? sign : "-") : sign === "-" || sign === "(" ? "" : sign) + valuePrefix;
valueSuffix = valueSuffix + (type === "s" ? prefixes[8 + prefixExponent / 3] : "") + (valueNegative && sign === "(" ? ")" : "");
// Break the formatted value into the integer “value” part that can be
// grouped, and fractional or exponential “suffix” part that is not.
if (maybeSuffix) {
i = -1, n = value.length;
while (++i < n) {
if (c = value.charCodeAt(i), 48 > c || c > 57) {
valueSuffix = (c === 46 ? decimal + value.slice(i + 1) : value.slice(i)) + valueSuffix;
value = value.slice(0, i);
break;
}
}
}
}
// If the fill character is not "0", grouping is applied before padding.
if (comma && !zero) value = group(value, Infinity);
// Compute the padding.
var length = valuePrefix.length + value.length + valueSuffix.length,
padding = length < width ? new Array(width - length + 1).join(fill) : "";
// If the fill character is "0", grouping is applied after padding.
if (comma && zero) value = group(padding + value, padding.length ? width - valueSuffix.length : Infinity), padding = "";
// Reconstruct the final output based on the desired alignment.
switch (align) {
case "<": value = valuePrefix + value + valueSuffix + padding; break;
case "=": value = valuePrefix + padding + value + valueSuffix; break;
case "^": value = padding.slice(0, length = padding.length >> 1) + valuePrefix + value + valueSuffix + padding.slice(length); break;
default: value = padding + valuePrefix + value + valueSuffix; break;
}
return numerals(value);
}
format.toString = function() {
return specifier + "";
};
return format;
}
function formatPrefix(specifier, value) {
var f = newFormat((specifier = formatSpecifier(specifier), specifier.type = "f", specifier)),
e = Math.max(-8, Math.min(8, Math.floor(exponent(value) / 3))) * 3,
k = Math.pow(10, -e),
prefix = prefixes[8 + e / 3];
return function(value) {
return f(k * value) + prefix;
};
}
return {
format: newFormat,
formatPrefix: formatPrefix
};
}