65 lines
1.7 KiB
JavaScript
65 lines
1.7 KiB
JavaScript
import number from "./number.js";
|
|
|
|
var reA = /[-+]?(?:\d+\.?\d*|\.?\d+)(?:[eE][-+]?\d+)?/g,
|
|
reB = new RegExp(reA.source, "g");
|
|
|
|
function zero(b) {
|
|
return function() {
|
|
return b;
|
|
};
|
|
}
|
|
|
|
function one(b) {
|
|
return function(t) {
|
|
return b(t) + "";
|
|
};
|
|
}
|
|
|
|
export default function(a, b) {
|
|
var bi = reA.lastIndex = reB.lastIndex = 0, // scan index for next number in b
|
|
am, // current match in a
|
|
bm, // current match in b
|
|
bs, // string preceding current number in b, if any
|
|
i = -1, // index in s
|
|
s = [], // string constants and placeholders
|
|
q = []; // number interpolators
|
|
|
|
// Coerce inputs to strings.
|
|
a = a + "", b = b + "";
|
|
|
|
// Interpolate pairs of numbers in a & b.
|
|
while ((am = reA.exec(a))
|
|
&& (bm = reB.exec(b))) {
|
|
if ((bs = bm.index) > bi) { // a string precedes the next number in b
|
|
bs = b.slice(bi, bs);
|
|
if (s[i]) s[i] += bs; // coalesce with previous string
|
|
else s[++i] = bs;
|
|
}
|
|
if ((am = am[0]) === (bm = bm[0])) { // numbers in a & b match
|
|
if (s[i]) s[i] += bm; // coalesce with previous string
|
|
else s[++i] = bm;
|
|
} else { // interpolate non-matching numbers
|
|
s[++i] = null;
|
|
q.push({i: i, x: number(am, bm)});
|
|
}
|
|
bi = reB.lastIndex;
|
|
}
|
|
|
|
// Add remains of b.
|
|
if (bi < b.length) {
|
|
bs = b.slice(bi);
|
|
if (s[i]) s[i] += bs; // coalesce with previous string
|
|
else s[++i] = bs;
|
|
}
|
|
|
|
// Special optimization for only a single match.
|
|
// Otherwise, interpolate each of the numbers and rejoin the string.
|
|
return s.length < 2 ? (q[0]
|
|
? one(q[0].x)
|
|
: zero(b))
|
|
: (b = q.length, function(t) {
|
|
for (var i = 0, o; i < b; ++i) s[(o = q[i]).i] = o.x(t);
|
|
return s.join("");
|
|
});
|
|
}
|