negateValue.js•771 B
export default function negateValue(value) {
value = `${value}`
if (value === '0') {
return '0'
}
// Flip sign of numbers
if (/^[+-]?(\d+|\d*\.\d+)(e[+-]?\d+)?(%|\w+)?$/.test(value)) {
return value.replace(/^[+-]?/, (sign) => (sign === '-' ? '' : '-'))
}
// What functions we support negating numeric values for
// var() isn't inherently a numeric function but we support it anyway
// The trigonometric functions are omitted because you'll need to use calc(…) with them _anyway_
// to produce generally useful results and that will be covered already
let numericFunctions = ['var', 'calc', 'min', 'max', 'clamp']
for (const fn of numericFunctions) {
if (value.includes(`${fn}(`)) {
return `calc(${value} * -1)`
}
}
}