Add constant ONEMILLI

for enhanced clarity of function `periodCompatibleWithTickformat`

Author: my-tien

src/constants/numerical.js

@@ -37,6 +37,7 @@ module.exports = {
     ONEHOUR: 3600000,
     ONEMIN: 60000,
     ONESEC: 1000,
+    ONEMILLI: 1,
     ONEMICROSEC: 0.001,
     /*
      * For fast conversion btwn world calendars and epoch ms, the Julian Day Number

src/plots/cartesian/axes.js

@@ -31,6 +31,7 @@ var HALFDAY = ONEDAY / 2;
 var ONEHOUR = constants.ONEHOUR;
 var ONEMIN = constants.ONEMIN;
 var ONESEC = constants.ONESEC;
+var ONEMILLI = constants.ONEMILLI;
 var ONEMICROSEC = constants.ONEMICROSEC;
 var MINUS_SIGN = constants.MINUS_SIGN;
 var BADNUM = constants.BADNUM;
@@ -4607,7 +4608,7 @@ function setShiftVal(ax, axShifts) {
 function periodCompatibleWithTickformat(period, tickformat) {
     return (
         /%f/.test(tickformat) ? period >= ONEMICROSEC :
-        /%L/.test(tickformat) ? period >= 1 :
+        /%L/.test(tickformat) ? period >= ONEMILLI :
         /%[SX]/.test(tickformat) ? period >= ONESEC :
         /%M/.test(tickformat) ? period >= ONEMIN :
         /%[HI]/.test(tickformat) ? period >= ONEHOUR :