TypeScript empty row in string literal-CodePudding

I want to create a string literal with the optional value numberOfResidents.

function mapBuildingToComment(building: Building) {
    return `
    ### Building information ###
    Street: ${building.address.street}
    HouseNumber: ${building.address.houseNumber}
    ${mapNumberOfResidents(building.numberOfResidents)}
    City: ${building.address.city}
    `
}

function mapNumberOfResidents(numberOfResidents?: string) {
    if (!numberOfResidents) return ''

    return `Number of residents: ${numberOfResidents}`
}

My problem now is, when numberOfResidents is undefined, there is an empty line in my output.

Output:
    ### Building information ###
    Street: Teststreet
    HouseNumber: 1

    City: Test

How can I achieve that there is no empty line and City is directly below the house number?

CodePudding user response：

remove the newline and add it only if you need it like

function mapBuildingToComment(building: typeof b) {
    return `
    ### Building information ###
    Street: ${building.address.street}
    HouseNumber: ${building.address.houseNumber}\
${building.numberOfResidents ? '\n    '   mapNumberOfResidents(building.numberOfResidents) : ''}
    City: ${building.address.city}
    `
}

function mapNumberOfResidents(numberOfResidents?: string) {
    if (!numberOfResidents) return ''

    return `Number of residents: ${numberOfResidents}`
}

const b = {address: {street: '123', houseNumber: 245, city: 'asd'}, numberOfResidents: '3'}
console.log(mapBuildingToComment(b))
b.numberOfResidents = ''
console.log(mapBuildingToComment(b))

another option is to remove empty lines from result with s.replaceAll(/\n\s (?=\n)/g, '')