You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 
 
 

55 lines
1.4 KiB

/*
* ToInteger() (E5 Section 9.4).
*
* ToInteger() appears in many places but its result is difficult to get out
* unaltered. Date.UTC() allows that for TimeClip() range if every argument
* is given as 0 except milliseconds. The arguments will then be ToNumber()
* coerced (which is a no-op), and milliseconds will then go through:
*
* - MakeTime: will return 0 + 0 + 0 + ToInteger(ms)
* - MakeDate: year1900_in_msec + ToInteger(ms)
* - TimeClip: year1900_in_msec + ToInteger(ms) or
* year1900_in_msec + (+0) + ToInteger(ms),
* or NaN if abs(ToInteger(ms)) > 8.64e15
*
* Negative zero will not survive this process but will be converted to a
* positive zero. The year 1900 replacement happens because of the explicit
* year handling step in E5 Section 15.9.4.3, step 8.
*/
/*===
0 -1000000000000
1 -10000000000
2 -1000000000
3 -100
4 -100
5 -100
6 -1
7 0
8 0
9 1
10 100
11 100
12 100
13 1000000000
14 10000000000
15 1000000000000
===*/
function simulateToNumber(v) {
var year1900 = Date.UTC(0, 0, 0, 0, 0, 0, 0).valueOf();
return Date.UTC(0, 0, 0, 0, 0, 0, v).valueOf() - year1900;
}
function test() {
[ -1e12, -1e10, -1e9, -100.9, -100.5, -100.1, -1, -0, +0, 1, 100.1, 100.5, 100.9,
1e9, 1e10, 1e12 ].forEach(function (v, i) {
print(i, simulateToNumber(v));
});
}
try {
test();
} catch (e) {
print(e.stack || e);
}