space-infix-ops 
While formatting preferences are very personal, a number of style guides require spaces around operators, such as:
var sum = 1 + 2;Proponents of this rule believe that it makes code easier to read and can more easily highlight potential errors, such as:
var sum = i+++2;While this is valid JavaScript syntax, it is hard to determine what the author intended.
Rule Details 
This rule is aimed at ensuring there are spaces around infix operators.
Options 
This rule accepts a single options argument with the following defaults:
"space-infix-ops": ["error", { "int32Hint": false }]int32Hint 
Set the int32Hint option to true (default is false) to allow write a|0 without space.
var foo = bar|0; // `foo` is forced to be signed 32 bit integerExamples of incorrect code for this rule:
/*eslint @stylistic/space-infix-ops: "error"*/
/*eslint-env es6*/
a+b
a+ b
a +b
a?b:c
const a={b:1};
var {b=0}=bar;
function foo(a=0) { }Examples of correct code for this rule:
/*eslint @stylistic/space-infix-ops: "error"*/
/*eslint-env es6*/
a + b
a       + b
a ? b : c
const a = {b:1};
var {b = 0} = bar;
function foo(a = 0) { }When Not To Use It 
You can turn this rule off if you are not concerned with the consistency of spacing around infix operators.
TypeScript Specific 
ts/space-infix-ops 
enum MyEnum {
  KEY = 'value',
}let value: string | number = 'value'Options 
This rule accepts the same options as the base rule plus the an option to disable type checking:
"space-infix-ops": ["error", { "int32Hint": false, "ignoreTypes": false }]ignoreTypes 
Set the ignoreTypes option to true (default is false) to allow write string|number without space.
var foo: string|number = bar;