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amysimmons/coercion-gotchas.md

Last active January 7, 2024 11:57
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coercion-gotchas.md 
false == "0" // true
// false gets coerced to 0
// "0" gets coerced to 0
// 0 == 0 is true 

false == 0 // true
// false gets coerced to 0
// 0 == 0 is true

false == "" // true
// false gets coerced to 0
// "" gets coerced to a number, 0
// 0 == 0 is true

false == [] // true
// false gets coerced to 0
// [] is an object so ToPrimitive would be called on it
// valueOf() would be consulted to find a primitive
// [].valueOf() would result in [], not a primitive value
// so [].toString() would be called, resulting in ""
// "" would then get coerced to a number, 0
// 0 == 0 is true

"" == 0 // true
// "" gets coerced to a number, 0
// 0 == 0 is true

"" == [] // true
// [] is an object so ToPrimitive would be called on it
// valueOf() would be consulted to find a primitive
// [].valueOf() would result in [], not a primitive value
// so [].toString() would be called, resulting in ""
// "" == "" is true

0 == [] // true
// [] is an object so ToPrimitive would be called on it
// valueOf() would be consulted to find a primitive
// [].valueOf() would result in [], not a primitive value
// so [].toString() would be called, resulting in ""
// "" would then get coerced to a number, 0
// 0 == 0 is true

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