JavaScript去除字符串中的空格

function trim(str) {
    return str.replace(/\s*/g, ‘‘);
}
console.log(‘=‘ + trim(‘ Hello World ! ‘) + ‘=‘);   // =HelloWorld!=

function trimMiddle(str) {
    let head = str.match(/^\s*\S*/)[0];
    let end = str.match(/\S*\s*$/)[0];
    let middle = str.replace(/(^\s*\S*)|(\S*\s*$)/g, ‘‘).replace(/\s*/g, ‘‘);
    return head + middle + end;
}
console.log(‘=‘ + trimMiddle(‘   Hello  World  !   ‘) + ‘=‘);   // =   HelloWorld!   =

function trimBothSides(str) {
    return str.replace(/^\s*|\s*$/g, ‘‘);
}
console.log(‘=‘ + trimBothSides(‘ Hello World!  ‘) + ‘=‘);  // =Hello World!=

console.log(‘=‘ + ‘   Hello World !   ‘.trim() + ‘=‘);      // =Hello World !=

function trimLeft(str) {
    return str.replace(/^\s*/, ‘‘);
}
console.log(‘=‘ + trimLeft(‘   Hello World!  ‘) + ‘=‘);     // =Hello World!  =

console.log(‘=‘ + ‘   Hello World !   ‘.trimLeft() + ‘=‘);      // =Hello World !   =

function trimRight(str) {
    return str.replace(/\s*$/, ‘‘);
}
console.log(‘=‘ + trimRight(‘   Hello World!   ‘) + ‘=‘);   // =   Hello World!=

console.log(‘=‘ + ‘   Hello World !   ‘.trimRight() + ‘=‘);     // =   Hello World !=