TypeError: Cannot read property startsWith of undefined

ubuntu_ulysses

import React from 'react'; import AttributeDescription from './AttributeDescription'; class CompEntry extends React.Component{ render(){ let description; if(this.props.description.startsWith("_")){ description= this.props.description.slice(1, this.props.description.length); } if(this.props.description.startsWith("__")){ description = this.props.description.slice(2, this.props.description.length); } return( <div> <div> <AttributeDescription...

Originally asked by kabison33 on Stack Exchange (stackoverflow) (CC BY-SA 4.0).

uphilltech

Great question — answering as the UphillTech team:

Check to make sure your property/object/variable is indeed a type of string - which is the only type to have this method extension. You won't necessarily get an interpreter/compiler error in either the typescript or HTML. In my case, my property (called 'name' perhaps confusingly) was actually a type of any . When I cast it to a string though...: // ERROR - Throws: "Cannot read properties of undefined ('startsWith') bool includes = this.name.startsWith('example'); // Works bool includes = String(this.name).startsWith('example');

Full answer by ouflak: https://stackoverflow.stackexchange.com/a/79678858 (CC BY-SA 4.0).

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