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Restrictions in Naming Properties

// Example of invalid key names const trainSchedule = { platform num: 10, // Invalid because of the space between words. 40 - 10 + 2: 30, // Expressions cannot be keys. +compartment: 'C' // The use of a + sign is invalid unless it is enclosed in quotations. }

JavaScript object key names must adhere to some restrictions to be valid. Key names must either be strings or valid identifier or variable names (i.e. special characters such as - are not allowed in key names that are not strings).

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