constant-compare-null-undefined.js

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load(libdir + "asserts.js");

function makeConstantCompareFn(val, op) {

  return new Function('val', `return val ${op} ${val};`);

  function testConstantCompareFn(fn, i, expectedOnSuccess) {

    assertEq(fn(i), expectedOnSuccess);

    // test with double values

    assertEq(fn(0.5), !expectedOnSuccess);

    assertEq(fn(-0.5), !expectedOnSuccess);

    // test with string values

    assertEq(fn(String(i)), !expectedOnSuccess);

    assertEq(fn(String(!i)), !expectedOnSuccess);

    // test with int values

    assertEq(fn(1), !expectedOnSuccess);

    assertEq(fn(0), !expectedOnSuccess);

    assertEq(fn(-1), !expectedOnSuccess);

    // test with BigInt values

    assertEq(fn(BigInt(1)), !expectedOnSuccess);

    // test with NaN

    assertEq(fn(NaN), !expectedOnSuccess);

    // test with Infinity

    assertEq(fn(Infinity), !expectedOnSuccess);

    assertEq(fn(-Infinity), !expectedOnSuccess);

    // test with object values

    assertEq(fn({}), !expectedOnSuccess);

    assertEq(fn([]), !expectedOnSuccess);

  testConstantCompareFn(makeConstantCompareFn(null, '==='), null, true);

  testConstantCompareFn(makeConstantCompareFn(null, '!=='), null, false);

  testConstantCompareFn(makeConstantCompareFn(undefined, '==='), undefined, true);

  testConstantCompareFn(makeConstantCompareFn(undefined, '!=='), undefined, false);