in escodegen.js [263:316]
function generateNumber(value) {
var result, point, temp, exponent, pos;
if (value !== value) {
throw new Error('Numeric literal whose value is NaN');
}
if (value < 0 || (value === 0 && 1 / value < 0)) {
throw new Error('Numeric literal whose value is negative');
}
if (value === 1 / 0) {
return json ? 'null' : renumber ? '1e400' : '1e+400';
}
result = '' + value;
if (!renumber || result.length < 3) {
return result;
}
point = result.indexOf('.');
if (!json && result.charCodeAt(0) === 0x30 /* 0 */ && point === 1) {
point = 0;
result = result.slice(1);
}
temp = result;
result = result.replace('e+', 'e');
exponent = 0;
if ((pos = temp.indexOf('e')) > 0) {
exponent = +temp.slice(pos + 1);
temp = temp.slice(0, pos);
}
if (point >= 0) {
exponent -= temp.length - point - 1;
temp = +(temp.slice(0, point) + temp.slice(point + 1)) + '';
}
pos = 0;
while (temp.charCodeAt(temp.length + pos - 1) === 0x30 /* 0 */) {
--pos;
}
if (pos !== 0) {
exponent -= pos;
temp = temp.slice(0, pos);
}
if (exponent !== 0) {
temp += 'e' + exponent;
}
if ((temp.length < result.length ||
(hexadecimal && value > 1e12 && Math.floor(value) === value && (temp = '0x' + value.toString(16)).length < result.length)) &&
+temp === value) {
result = temp;
}
return result;
}