number-tostring.js

Google浏览器V8内核代码

assertEquals("0.000000060", (0.00000006).toFixed(9));
assertEquals("0.0000000600", (0.00000006).toFixed(10));
assertEquals("0", (0).toFixed(0));
assertEquals("0.0", (0).toFixed(1));
assertEquals("0.00", (0).toFixed(2));

assertEquals("-1.1111111111111111e+21", (-1111111111111111111111).toFixed(8));
assertEquals("-0.1", (-0.1).toFixed(1));
assertEquals("-0.10", (-0.1).toFixed(2));
assertEquals("-0.100", (-0.1).toFixed(3));
assertEquals("-0.01", (-0.01).toFixed(2));
assertEquals("-0.010", (-0.01).toFixed(3));
assertEquals("-0.0100", (-0.01).toFixed(4));
assertEquals("-0.00", (-0.001).toFixed(2));
assertEquals("-0.001", (-0.001).toFixed(3));
assertEquals("-0.0010", (-0.001).toFixed(4));
assertEquals("-1.0000", (-1).toFixed(4));
assertEquals("-1.0", (-1).toFixed(1));
assertEquals("-1", (-1).toFixed(0));
assertEquals("-1", (-1.1).toFixed(0));
assertEquals("-12", (-12.1).toFixed(0));
assertEquals("-1", (-1.12).toFixed(0));
assertEquals("-12", (-12.12).toFixed(0));
assertEquals("-0.0000006", (-0.0000006).toFixed(7));
assertEquals("-0.00000006", (-0.00000006).toFixed(8));
assertEquals("-0.000000060", (-0.00000006).toFixed(9));
assertEquals("-0.0000000600", (-0.00000006).toFixed(10));
assertEquals("0", (-0).toFixed(0));
assertEquals("0.0", (-0).toFixed(1));
assertEquals("0.00", (-0).toFixed(2));

assertEquals("1000", (1000).toFixed());
assertEquals("0", (0.00001).toFixed());
assertEquals("0.00001", (0.00001).toFixed(5));
assertEquals("0.00000000000000000010", (0.0000000000000000001).toFixed(20));
assertEquals("0.00001000000000000", (0.00001).toFixed(17));
assertEquals("1.00000000000000000", (1).toFixed(17));
assertEquals("1000000000000000128", (1000000000000000128).toFixed());
assertEquals("100000000000000128.0", (100000000000000128).toFixed(1));
assertEquals("10000000000000128.00", (10000000000000128).toFixed(2));
assertEquals("10000000000000128.00000000000000000000", (10000000000000128).toFixed(20));
assertEquals("0", (0).toFixed());
assertEquals("-42.000", ((-42).toFixed(3)));
assertEquals("-1000000000000000128", (-1000000000000000128).toFixed());
assertEquals("-0.00000000000000000010", (-0.0000000000000000001).toFixed(20));
assertEquals("0.12312312312312299889", (0.123123123123123).toFixed(20));
// Test that we round up even when the last digit generated is even.
// dtoa does not do this in its original form.
assertEquals("1", 0.5.toFixed(0), "0.5.toFixed(0)");
assertEquals("-1", -0.5.toFixed(0), "-0.5.toFixed(0)");
assertEquals("1.3", 1.25.toFixed(1), "1.25.toFixed(1)");
// This is bizare, but Spidermonkey and KJS behave the same.
assertEquals("234.2040", (234.20405).toFixed(4), "234.2040.toFixed(4)");
assertEquals("234.2041", (234.2040506).toFixed(4));

// ----------------------------------------------------------------------
// toExponential
assertEquals("1e+0", (1).toExponential());
assertEquals("1.1e+1", (11).toExponential());
assertEquals("1.12e+2", (112).toExponential());
assertEquals("1e+0", (1).toExponential(0));
assertEquals("1e+1", (11).toExponential(0));
assertEquals("1e+2", (112).toExponential(0));
assertEquals("1.0e+0", (1).toExponential(1));
assertEquals("1.1e+1", (11).toExponential(1));
assertEquals("1.1e+2", (112).toExponential(1));
assertEquals("1.00e+0", (1).toExponential(2));
assertEquals("1.10e+1", (11).toExponential(2));
assertEquals("1.12e+2", (112).toExponential(2));
assertEquals("1.000e+0", (1).toExponential(3));
assertEquals("1.100e+1", (11).toExponential(3));
assertEquals("1.120e+2", (112).toExponential(3));
assertEquals("1e-1", (0.1).toExponential());
assertEquals("1.1e-1", (0.11).toExponential());
assertEquals("1.12e-1", (0.112).toExponential());
assertEquals("1e-1", (0.1).toExponential(0));
assertEquals("1e-1", (0.11).toExponential(0));
assertEquals("1e-1", (0.112).toExponential(0));
assertEquals("1.0e-1", (0.1).toExponential(1));
assertEquals("1.1e-1", (0.11).toExponential(1));
assertEquals("1.1e-1", (0.112).toExponential(1));
assertEquals("1.00e-1", (0.1).toExponential(2));
assertEquals("1.10e-1", (0.11).toExponential(2));
assertEquals("1.12e-1", (0.112).toExponential(2));
assertEquals("1.000e-1", (0.1).toExponential(3));
assertEquals("1.100e-1", (0.11).toExponential(3));
assertEquals("1.120e-1", (0.112).toExponential(3));

assertEquals("-1e+0", (-1).toExponential());
assertEquals("-1.1e+1", (-11).toExponential());
assertEquals("-1.12e+2", (-112).toExponential());
assertEquals("-1e+0", (-1).toExponential(0));
assertEquals("-1e+1", (-11).toExponential(0));
assertEquals("-1e+2", (-112).toExponential(0));
assertEquals("-1.0e+0", (-1).toExponential(1));
assertEquals("-1.1e+1", (-11).toExponential(1));
assertEquals("-1.1e+2", (-112).toExponential(1));
assertEquals("-1.00e+0", (-1).toExponential(2));
assertEquals("-1.10e+1", (-11).toExponential(2));
assertEquals("-1.12e+2", (-112).toExponential(2));
assertEquals("-1.000e+0", (-1).toExponential(3));
assertEquals("-1.100e+1", (-11).toExponential(3));
assertEquals("-1.120e+2", (-112).toExponential(3));
assertEquals("-1e-1", (-0.1).toExponential());
assertEquals("-1.1e-1", (-0.11).toExponential());
assertEquals("-1.12e-1", (-0.112).toExponential());
assertEquals("-1e-1", (-0.1).toExponential(0));
assertEquals("-1e-1", (-0.11).toExponential(0));
assertEquals("-1e-1", (-0.112).toExponential(0));
assertEquals("-1.0e-1", (-0.1).toExponential(1));
assertEquals("-1.1e-1", (-0.11).toExponential(1));
assertEquals("-1.1e-1", (-0.112).toExponential(1));
assertEquals("-1.00e-1", (-0.1).toExponential(2));
assertEquals("-1.10e-1", (-0.11).toExponential(2));
assertEquals("-1.12e-1", (-0.112).toExponential(2));
assertEquals("-1.000e-1", (-0.1).toExponential(3));
assertEquals("-1.100e-1", (-0.11).toExponential(3));
assertEquals("-1.120e-1", (-0.112).toExponential(3));

assertEquals("NaN", (NaN).toExponential(2));
assertEquals("Infinity", (Infinity).toExponential(2));
assertEquals("-Infinity", (-Infinity).toExponential(2));
assertEquals("1e+0", (1).toExponential(0));
assertEquals("0e+0", (0).toExponential());
assertEquals("0.00e+0", (0).toExponential(2));
assertEquals("1e+1", (11.2356).toExponential(0));
assertEquals("1.1236e+1", (11.2356).toExponential(4));
assertEquals("1.1236e-4", (0.000112356).toExponential(4));
assertEquals("-1.1236e-4", (-0.000112356).toExponential(4));
assertEquals("1.12356e-4", (0.000112356).toExponential());
assertEquals("-1.12356e-4", (-0.000112356).toExponential());

// ----------------------------------------------------------------------
// toPrecision
assertEquals("NaN", (NaN).toPrecision(1));
assertEquals("Infinity", (Infinity).toPrecision(2));
assertEquals("-Infinity", (-Infinity).toPrecision(2));
assertEquals("0.000555000000000000", (0.000555).toPrecision(15));
assertEquals("5.55000000000000e-7", (0.000000555).toPrecision(15));
assertEquals("-5.55000000000000e-7", (-0.000000555).toPrecision(15));
assertEquals("1e+8", (123456789).toPrecision(1));
assertEquals("123456789", (123456789).toPrecision(9));
assertEquals("1.2345679e+8", (123456789).toPrecision(8));
assertEquals("1.234568e+8", (123456789).toPrecision(7));
assertEquals("-1.234568e+8", (-123456789).toPrecision(7));
assertEquals("-1.2e-9", Number(-.0000000012345).toPrecision(2));
assertEquals("-1.2e-8", Number(-.000000012345).toPrecision(2));
assertEquals("-1.2e-7", Number(-.00000012345).toPrecision(2));
assertEquals("-0.0000012", Number(-.0000012345).toPrecision(2));
assertEquals("-0.000012", Number(-.000012345).toPrecision(2));
assertEquals("-0.00012", Number(-.00012345).toPrecision(2));
assertEquals("-0.0012", Number(-.0012345).toPrecision(2));
assertEquals("-0.012", Number(-.012345).toPrecision(2));
assertEquals("-0.12", Number(-.12345).toPrecision(2));
assertEquals("-1.2", Number(-1.2345).toPrecision(2));
assertEquals("-12", Number(-12.345).toPrecision(2));
assertEquals("-1.2e+2", Number(-123.45).toPrecision(2));
assertEquals("-1.2e+3", Number(-1234.5).toPrecision(2));
assertEquals("-1.2e+4", Number(-12345).toPrecision(2));
assertEquals("-1.235e+4", Number(-12345.67).toPrecision(4));
assertEquals("-1.234e+4", Number(-12344.67).toPrecision(4));
// Test that we round up even when the last digit generated is even.
// dtoa does not do this in its original form.
assertEquals("1.3", 1.25.toPrecision(2), "1.25.toPrecision(2)");
assertEquals("1.4", 1.35.toPrecision(2), "1.35.toPrecision(2)");